diff --git a/composer.json b/composer.json
index 89260f2..ce327cd 100644
--- a/composer.json
+++ b/composer.json
@@ -32,16 +32,19 @@
         "psr-4": { "Omnipay\\PayU\\" : "src/" }
     },
     "require": {
+        "php": "^7.2|^8",
+        "ext-curl": "*",
         "ext-json": "*",
-        "omnipay/common": "^2.5",
+        "omnipay/common": "^3",
         "openpayu/openpayu_php_sdk": "^2.2"
     },
     "require-dev": {
-        "omnipay/tests": "^2.1",
-        "symfony/var-dumper": "^2.7",
-        "mockery/mockery": "^0.9.5",
-        "vlucas/phpdotenv": "^2.3",
-        "phpunit/phpunit": "3.7.*",
-        "phpstan/phpstan": "^0.12.42"
+        "omnipay/tests": "^4.1",
+        "symfony/var-dumper": "^5.3",
+        "mockery/mockery": "^1.4",
+        "vlucas/phpdotenv": "^5.3",
+        "phpunit/phpunit": "^9",
+        "phpstan/phpstan": "^0.12.9",
+        "php-http/guzzle7-adapter": "^1.0"
     }
 }
diff --git a/examples/test-finish.php b/examples/test-finish.php
index a018f60..4627353 100644
--- a/examples/test-finish.php
+++ b/examples/test-finish.php
@@ -3,19 +3,22 @@
 require '../vendor/autoload.php';
 
 use Omnipay\PayU\GatewayFactory;
+use Omnipay\PayU\Messages\CompletePurchaseResponse;
 
-$dotenv = new Dotenv\Dotenv(__DIR__ . '/..');
+$dotenv = Dotenv\Dotenv::createImmutable(__DIR__ . '/..');
 $dotenv->load();
 
 // default is official sandbox
-$posId = isset($_ENV['POS_ID']) ? $_ENV['POS_ID'] : '300046';
-$secondKey = isset($_ENV['SECOND_KEY']) ? $_ENV['SECOND_KEY'] : '0c017495773278c50c7b35434017b2ca';
-$oAuthClientSecret = isset($_ENV['OAUTH_CLIENT_SECRET']) ? $_ENV['OAUTH_CLIENT_SECRET'] : 'c8d4b7ac61758704f38ed5564d8c0ae0';
+$posId = isset($_ENV['POS_ID']) ? $_ENV['POS_ID'] : '300746';
+$secondKey = isset($_ENV['SECOND_KEY']) ? $_ENV['SECOND_KEY'] : 'b6ca15b0d1020e8094d9b5f8d163db54';
+$oAuthClientSecret = isset($_ENV['OAUTH_CLIENT_SECRET']) ? $_ENV['OAUTH_CLIENT_SECRET'] : '2ee86a66e5d97e3fadc400c9f19b065d';
+$posAuthKey = isset($_ENV['POS_AUTH_KEY']) ? $_ENV['POS_AUTH_KEY'] : '300746';
 
-$gateway = GatewayFactory::createInstance($posId, $secondKey, $oAuthClientSecret, true);
+$gateway = GatewayFactory::createInstance($posId, $secondKey, $oAuthClientSecret, true, $posAuthKey);
 
 try {
     $completeRequest = ['transactionReference' => 'J9R4JP3F2G160825GUEST000P01'];
+    /** @var CompletePurchaseResponse $response */
     $response = $gateway->completePurchase($completeRequest);
 
     echo "Is Successful: " . $response->isSuccessful() . PHP_EOL;
@@ -24,6 +27,8 @@
     echo "PaymentId: " , $response->getTransactionReference() . PHP_EOL;
     echo "Data: " . var_export($response->getData(), true) . PHP_EOL;
 
+} catch (OpenPayU_Exception $e) {
+    dump($e->getMessage());
 } catch (Exception $e) {
     dump((string)$e);
 }
diff --git a/examples/test-notification.php b/examples/test-notification.php
index 88d9148..c1c5f1b 100644
--- a/examples/test-notification.php
+++ b/examples/test-notification.php
@@ -5,14 +5,16 @@
 use Omnipay\PayU\GatewayFactory;
 use Symfony\Component\HttpFoundation\Request;
 
-$dotenv = new Dotenv\Dotenv(__DIR__ . '/..');
+$dotenv = Dotenv\Dotenv::createImmutable(__DIR__ . '/..');
 $dotenv->load();
 
 // default is official sandbox
-$posId = isset($_ENV['POS_ID']) ? $_ENV['POS_ID'] : '300046';
-$secondKey = isset($_ENV['SECOND_KEY']) ? $_ENV['SECOND_KEY'] : '0c017495773278c50c7b35434017b2ca';
-$oAuthClientSecret = isset($_ENV['OAUTH_CLIENT_SECRET']) ? $_ENV['OAUTH_CLIENT_SECRET'] : 'c8d4b7ac61758704f38ed5564d8c0ae0';
-$posAuthKey = isset($_ENV['POS_AUTH_KEY']) ? $_ENV['POS_AUTH_KEY'] : null; // Official sandbox does not provide signature key
+$posId = isset($_ENV['POS_ID']) ? $_ENV['POS_ID'] : '300746';
+$secondKey = isset($_ENV['SECOND_KEY']) ? $_ENV['SECOND_KEY'] : 'b6ca15b0d1020e8094d9b5f8d163db54';
+$oAuthClientSecret = isset($_ENV['OAUTH_CLIENT_SECRET']) ? $_ENV['OAUTH_CLIENT_SECRET'] : '2ee86a66e5d97e3fadc400c9f19b065d';
+$posAuthKey = isset($_ENV['POS_AUTH_KEY']) ? $_ENV['POS_AUTH_KEY'] : '300746';
+
+$gateway = GatewayFactory::createInstance($posId, $secondKey, $oAuthClientSecret, true, $posAuthKey);
 
 $content = '{"order":{"orderId":"NN18KW7XJG160830GUEST000P01","extOrderId":"57c56b16d22e1","orderCreateDate":"2016-08-30T13:16:39.641+02:00","notifyUrl":"http://52.58.177.216/online-payments/uuid/notify","customerIp":"80.188.133.34","merchantPosId":"300293","description":"Shopping at myStore.com","currencyCode":"PLN","totalAmount":"15000","status":"PENDING","products":[{"name":"Lenovo ThinkPad Edge E540","unitPrice":"15000","quantity":"1"}]},"localReceiptDateTime":"2016-08-30T13:17:14.502+02:00","properties":[{"name":"PAYMENT_ID","value":"72829425"}]}';
 $httpRequest = Request::create('/notify', 'POST', [], [], [], [], $content);
diff --git a/examples/test.php b/examples/test.php
index bad80ec..b19bb94 100644
--- a/examples/test.php
+++ b/examples/test.php
@@ -2,18 +2,19 @@
 
 require '../vendor/autoload.php';
 
-use Guzzle\Http\Exception\ClientErrorResponseException;
 use Omnipay\PayU\GatewayFactory;
+use Omnipay\PayU\Messages\PurchaseResponse;
 
-$dotenv = new Dotenv\Dotenv(__DIR__ . '/..');
+$dotenv = Dotenv\Dotenv::createImmutable(__DIR__ . '/..');
 $dotenv->load();
 
 // default is official sandbox
-$posId = isset($_ENV['POS_ID']) ? $_ENV['POS_ID'] : '300046';
-$secondKey = isset($_ENV['SECOND_KEY']) ? $_ENV['SECOND_KEY'] : '0c017495773278c50c7b35434017b2ca';
-$oAuthClientSecret = isset($_ENV['OAUTH_CLIENT_SECRET']) ? $_ENV['OAUTH_CLIENT_SECRET'] : 'c8d4b7ac61758704f38ed5564d8c0ae0';
+$posId = isset($_ENV['POS_ID']) ? $_ENV['POS_ID'] : '300746';
+$secondKey = isset($_ENV['SECOND_KEY']) ? $_ENV['SECOND_KEY'] : 'b6ca15b0d1020e8094d9b5f8d163db54';
+$oAuthClientSecret = isset($_ENV['OAUTH_CLIENT_SECRET']) ? $_ENV['OAUTH_CLIENT_SECRET'] : '2ee86a66e5d97e3fadc400c9f19b065d';
+$posAuthKey = isset($_ENV['POS_AUTH_KEY']) ? $_ENV['POS_AUTH_KEY'] : '300746';
 
-$gateway = GatewayFactory::createInstance($posId, $secondKey, $oAuthClientSecret, true);
+$gateway = GatewayFactory::createInstance($posId, $secondKey, $oAuthClientSecret, true, $posAuthKey);
 
 try {
     $orderNo = uniqid();
@@ -53,6 +54,7 @@
         ]
     ];
 
+    /** @var PurchaseResponse $response */
     $response = $gateway->purchase($purchaseRequest);
 
     echo "TransactionId: " . $response->getTransactionId() . PHP_EOL;
@@ -62,7 +64,8 @@
 
     // Payment init OK, redirect to the payment gateway
     echo $response->getRedirectUrl() . PHP_EOL;
-} catch (ClientErrorResponseException $e) {
+} catch (OpenPayU_Exception $e) {
+    dump($e->getMessage());
+} catch (Exception $e) {
     dump((string)$e);
-    dump($e->getResponse()->getBody(true));
-}
\ No newline at end of file
+}
diff --git a/src/Gateway.php b/src/Gateway.php
index b0edd00..3c8adde 100644
--- a/src/Gateway.php
+++ b/src/Gateway.php
@@ -3,86 +3,79 @@
 namespace Omnipay\PayU;
 
 use Omnipay\Common\AbstractGateway;
-use Omnipay\PayU\Messages\AccessTokenRequest;
-use Omnipay\PayU\Messages\AccessTokenResponse;
+use Omnipay\Common\Message\ResponseInterface;
 use Omnipay\PayU\Messages\CompletePurchaseRequest;
 use Omnipay\PayU\Messages\CompletePurchaseResponse;
 use Omnipay\PayU\Messages\Notification;
 use Omnipay\PayU\Messages\PurchaseRequest;
 use Omnipay\PayU\Messages\PurchaseResponse;
+use OpenPayU_Configuration;
+use OpenPayU_Exception;
+use OpenPayU_Exception_Configuration;
 
 class Gateway extends AbstractGateway
 {
-    const URL_SANDBOX = 'https://secure.snd.payu.com';
-    const URL_PRODUCTION = 'https://secure.payu.com';
+    const ENV_TEST = 'sandbox';
+    const ENV_PRODUCTION = 'secure';
 
     /**
      * Get gateway display name
      */
-    public function getName()
+    public function getName(): string
     {
         return 'PayU';
     }
 
     /**
-     * @return AccessTokenResponse
+     * @param array $parameters
+     * @return $this|Gateway
+     * @throws OpenPayU_Exception_Configuration
      */
-    public function getAccessToken()
+    public function initialize(array $parameters = []): self
     {
-        $request = parent::createRequest(AccessTokenRequest::class, [
-            'clientId'     => $this->getParameter('posId'),
-            'clientSecret' => $this->getParameter('clientSecret'),
-            'apiUrl'       => $this->getApiUrl()
-        ]);
-        $response = $request->send();
-
-        return $response;
+        parent::initialize($parameters);
+
+        OpenPayU_Configuration::setEnvironment($this->getEnvironment());
+        OpenPayU_Configuration::setOauthGrantType('client_credentials');
+        OpenPayU_Configuration::setMerchantPosId($this->getParameter('posId'));
+        OpenPayU_Configuration::setSignatureKey($this->getParameter('secondKey'));
+        OpenPayU_Configuration::setOauthClientId($this->getParameter('posAuthKey'));
+        OpenPayU_Configuration::setOauthClientSecret($this->getParameter('clientSecret'));
+
+        return $this;
     }
 
     /**
-     * @param array $parameters
-     * @return PurchaseResponse
+     * @param array $options
+     * @throws OpenPayU_Exception
+     * @return PurchaseResponse|ResponseInterface
      */
-    public function purchase(array $parameters = [])
+    public function purchase(array $options = []): ResponseInterface
     {
-        $this->setAccessToken($this->getAccessToken()->getAccessToken());
-        $request = parent::createRequest(PurchaseRequest::class, $parameters);
-        $response = $request->send();
+        $request = $this->createRequest(PurchaseRequest::class, $options);
 
-        return $response;
+        return $request->send();
     }
 
     /**
-     * @param array $parameters
-     * @return CompletePurchaseResponse
+     * @param array $options
+     * @throws OpenPayU_Exception
+     * @return CompletePurchaseResponse|ResponseInterface
      */
-    public function completePurchase(array $parameters = [])
+    public function completePurchase(array $options = []): ResponseInterface
     {
-        $this->setAccessToken($this->getAccessToken()->getAccessToken());
-        $request = self::createRequest(CompletePurchaseRequest::class, $parameters);
-        $response = $request->send();
+        $request = $this->createRequest(CompletePurchaseRequest::class, $options);
 
-        return $response;
+        return $request->send();
     }
 
-    public function acceptNotification()
+    public function acceptNotification(): Notification
     {
         return new Notification($this->httpRequest, $this->httpClient, $this->getParameter('secondKey'));
     }
 
-    /**
-     * @return string
-     */
-    private function getApiUrl()
-    {
-        if ($this->getTestMode()) {
-            return self::URL_SANDBOX;
-        } else {
-            return self::URL_PRODUCTION;
-        }
-    }
-
-    public function getDefaultParameters()
+    /** @return array<string, mixed> */
+    public function getDefaultParameters(): array
     {
         return [
             'posId'        => '',
@@ -96,7 +89,7 @@ public function getDefaultParameters()
     /**
      * @param string $secondKey
      */
-    public function setSecondKey($secondKey)
+    public function setSecondKey(string $secondKey): void
     {
         $this->setParameter('secondKey', $secondKey);
     }
@@ -104,7 +97,7 @@ public function setSecondKey($secondKey)
     /**
      * @param string $posId
      */
-    public function setPosId($posId)
+    public function setPosId(string $posId): void
     {
         $this->setParameter('posId', $posId);
     }
@@ -112,7 +105,7 @@ public function setPosId($posId)
     /**
      * @param string $clientSecret
      */
-    public function setClientSecret($clientSecret)
+    public function setClientSecret(string $clientSecret): void
     {
         $this->setParameter('clientSecret', $clientSecret);
     }
@@ -120,26 +113,17 @@ public function setClientSecret($clientSecret)
     /**
      * @param string|null $posAuthKey
      */
-    public function setPosAuthKey($posAuthKey = null)
+    public function setPosAuthKey(string $posAuthKey = null): void
     {
         $this->setParameter('posAuthKey', $posAuthKey);
     }
 
-    public function initialize(array $parameters = [])
-    {
-        parent::initialize($parameters);
-        $this->setApiUrl($this->getApiUrl());
-
-        return $this;
-    }
-
-    private function setApiUrl($apiUrl)
+    private function getEnvironment(): string
     {
-        $this->setParameter('apiUrl', $apiUrl);
-    }
+        if ($this->getTestMode()) {
+            return self::ENV_TEST;
+        }
 
-    private function setAccessToken($accessToken)
-    {
-        $this->setParameter('accessToken', $accessToken);
+        return self::ENV_PRODUCTION;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Messages/AccessTokenRequest.php b/src/Messages/AccessTokenRequest.php
deleted file mode 100644
index 4002135..0000000
--- a/src/Messages/AccessTokenRequest.php
+++ /dev/null
@@ -1,61 +0,0 @@
-<?php
-namespace Omnipay\PayU\Messages;
-
-use Omnipay\Common\Message\AbstractRequest;
-
-class AccessTokenRequest extends AbstractRequest
-{
-
-    /** @var string */
-    private $apiUrl;
-
-    /**
-     * @param string $clientId
-     */
-    public function setClientId($clientId)
-    {
-        $this->setParameter('clientId', $clientId);
-    }
-
-    /**
-     * @param string $clientSecret
-     */
-    public function setClientSecret($clientSecret)
-    {
-        $this->setParameter('clientSecret', $clientSecret);
-    }
-
-    public function sendData($data)
-    {
-        $authorizeUrl = $this->apiUrl . '/pl/standard/user/oauth/authorize';
-
-        $headers = [
-            'Accept' => 'application/json',
-            'ContentType' => 'application/json',
-        ];
-        $tokenData = $this->httpClient->post($authorizeUrl, $headers, $data)->send();
-
-        $response = new AccessTokenResponse($this, $tokenData->json());
-        return $response;
-    }
-
-    /**
-     * @return array
-     */
-    public function getData()
-    {
-        return [
-            'grant_type' => 'client_credentials',
-            'client_id' => $this->parameters->get('clientId'),
-            'client_secret' => $this->parameters->get('clientSecret'),
-        ];
-    }
-
-    /**
-     * @param string $apiUrl
-     */
-    public function setApiUrl($apiUrl)
-    {
-        $this->apiUrl = $apiUrl;
-    }
-}
\ No newline at end of file
diff --git a/src/Messages/AccessTokenResponse.php b/src/Messages/AccessTokenResponse.php
deleted file mode 100644
index ca406e2..0000000
--- a/src/Messages/AccessTokenResponse.php
+++ /dev/null
@@ -1,31 +0,0 @@
-<?php
-namespace Omnipay\PayU\Messages;
-
-use Omnipay\Common\Message\AbstractResponse;
-
-class AccessTokenResponse extends AbstractResponse
-{
-
-    /**
-     * @return boolean
-     */
-    public function isSuccessful()
-    {
-        return is_array($this->data)
-            && isset($this->data['access_token'])
-            && is_string($this->data['access_token'])
-            && isset($this->data['token_type'])
-            && is_string($this->data['token_type']);
-    }
-
-    /**
-     * @return string
-     */
-    public function getAccessToken()
-    {
-        $completeToken = sprintf('%s %s', ucfirst($this->data['token_type']), $this->data['access_token']);
-
-        return $completeToken;
-    }
-
-}
\ No newline at end of file
diff --git a/src/Messages/CompletePurchaseRequest.php b/src/Messages/CompletePurchaseRequest.php
index 797059b..dfbc230 100644
--- a/src/Messages/CompletePurchaseRequest.php
+++ b/src/Messages/CompletePurchaseRequest.php
@@ -1,46 +1,43 @@
 <?php
 namespace Omnipay\PayU\Messages;
 
+use Exception;
 use Omnipay\Common\Message\AbstractRequest;
 use Omnipay\Common\Message\ResponseInterface;
+use OpenPayU_Exception;
+use OpenPayU_Order;
 
 class CompletePurchaseRequest extends AbstractRequest
 {
 
-    public function setAccessToken($accessToken)
+    public function setAccessToken(string $accessToken): void
     {
         $this->setParameter('accessToken', $accessToken);
     }
 
-    public function setApiUrl($apiUrl)
-    {
-        $this->setParameter('apiUrl', $apiUrl);
-    }
-
     /**
-     * @return array
+     * @return array<string, mixed>
      */
-    public function getData()
+    public function getData(): array
     {
         return $this->getParameters();
     }
 
     /**
-     * @param  mixed $data The data to send
-     * @return ResponseInterface
+     * @param mixed $data The data to send
+     * @return ResponseInterface|CompletePurchaseResponse
+     * @throws OpenPayU_Exception
+     * @throws Exception
      */
-    public function sendData($data)
+    public function sendData($data): ResponseInterface
     {
-        $headers = [
-            'Accept'        => 'application/json',
-            'Content-Type'  => 'application/json',
-            'Authorization' => $data['accessToken']
-        ];
-        $url = $data['apiUrl'] . '/api/v2_1/orders/' . urlencode($this->getTransactionReference());
-        $httpRequest = $this->httpClient->get($url, $headers);
-        $httpResponse = $httpRequest->send();
-
-        $response = new CompletePurchaseResponse($this, $httpResponse->json());
+        $payUResponse = OpenPayU_Order::retrieve($this->getTransactionReference());
+
+        if (!$payUResponse) {
+            throw new Exception('Could not fetch order data');
+        }
+
+        $response = new CompletePurchaseResponse($this, $payUResponse->getResponse());
 
         return $this->response = $response;
     }
diff --git a/src/Messages/CompletePurchaseResponse.php b/src/Messages/CompletePurchaseResponse.php
index 97c1386..ad0216b 100644
--- a/src/Messages/CompletePurchaseResponse.php
+++ b/src/Messages/CompletePurchaseResponse.php
@@ -9,7 +9,7 @@ class CompletePurchaseResponse extends AbstractResponse
     /**
      * @return boolean
      */
-    public function isSuccessful()
+    public function isSuccessful(): bool
     {
         return 'COMPLETED' === $this->getCode();
     }
@@ -17,16 +17,16 @@ public function isSuccessful()
     /**
      * @return string|null
      */
-    public function getTransactionId()
+    public function getTransactionId(): ?string
     {
-        if (isset($this->data['orders'][0]['extOrderId']) && !empty($this->data['orders'][0]['extOrderId'])) {
-            return (string) $this->data['orders'][0]['extOrderId'];
+        if (isset($this->data->orders[0]->extOrderId) && !empty($this->data->orders[0]->extOrderId)) {
+            return (string) $this->data->orders[0]->extOrderId;
         }
 
         return null;
     }
 
-    public function isCancelled()
+    public function isCancelled(): bool
     {
         return in_array($this->getCode(), ['CANCELED', 'REJECTED'], true);
     }
@@ -35,10 +35,10 @@ public function isCancelled()
      * PAYMENT_ID is not present for transaction in state PENDING
      * @return null|string
      */
-    public function getTransactionReference()
+    public function getTransactionReference(): ?string
     {
-        if (isset($this->data['orders'][0]['orderId']) && !empty($this->data['orders'][0]['orderId'])) {
-            return (string) $this->data['orders'][0]['orderId'];
+        if (isset($this->data->orders[0]->orderId) && !empty($this->data->orders[0]->orderId)) {
+            return (string) $this->data->orders[0]->orderId;
         }
 
         return null;
@@ -49,12 +49,12 @@ public function getTransactionReference()
      *
      * @return string
      */
-    public function getCode()
+    public function getCode(): string
     {
-        return $this->data['orders'][0]['status'];
+        return $this->data->orders[0]->status;
     }
 
-    public function isPending()
+    public function isPending(): bool
     {
         return in_array($this->getCode(), ['PENDING', 'WAITING_FOR_CONFIRMATION', 'NEW']);
     }
@@ -62,18 +62,8 @@ public function isPending()
     /**
      * @return string|null
      */
-    public function getPaymentReference()
+    public function getPaymentReference(): ?string
     {
-        if (isset($this->data['properties'])) {
-            $properties = $this->data['properties'];
-            $paymentIdProperty = array_filter($properties, function ($item) {
-                return $item['name'] === 'PAYMENT_ID';
-            });
-            if (isset($paymentIdProperty[0]['value'])) {
-                return (string)$paymentIdProperty[0]['value'];
-            }
-        };
-
-        return null;
+        return $this->getTransactionReference();
     }
-}
\ No newline at end of file
+}
diff --git a/src/Messages/Notification.php b/src/Messages/Notification.php
index c72f7d2..8060905 100644
--- a/src/Messages/Notification.php
+++ b/src/Messages/Notification.php
@@ -2,9 +2,8 @@
 
 namespace Omnipay\PayU\Messages;
 
-use Guzzle\Http\Client;
-use Guzzle\Http\ClientInterface;
 use Omnipay\Common\Exception\InvalidRequestException;
+use Omnipay\Common\Http\Client;
 use Omnipay\Common\Message\NotificationInterface;
 use OpenPayU_Util;
 use stdClass;
@@ -21,7 +20,7 @@ class Notification implements NotificationInterface
     /** @var Request */
     private $httpRequest;
 
-    /** @var Client|ClientInterface */
+    /** @var Client */
     private $httpClient;
 
     /** @var string */
@@ -74,10 +73,10 @@ public function __construct($httpRequest, $httpClient, $secondKey)
     /**
      * Gateway Reference
      *
-     * @return string A reference provided by the gateway to represent this transaction
+     * @return null|string A reference provided by the gateway to represent this transaction
      * @throws InvalidRequestException
      */
-    public function getTransactionReference()
+    public function getTransactionReference(): ?string
     {
         if (isset($this->getData()->order->extOrderId) && !empty($this->getData()->order->extOrderId)) {
             return (string) $this->getData()->order->extOrderId;
@@ -132,7 +131,7 @@ private function getSignature(Request $request)
      * @return string Transaction status, one of {@see STATUS_COMPLETED}, {@see #STATUS_PENDING} or {@see #STATUS_FAILED}.
      * @throws InvalidRequestException
      */
-    public function getTransactionStatus()
+    public function getTransactionStatus(): string
     {
         if ($this->getData()) {
             $status = $this->getData()->order->status;
diff --git a/src/Messages/PurchaseRequest.php b/src/Messages/PurchaseRequest.php
index 49f527d..817719d 100644
--- a/src/Messages/PurchaseRequest.php
+++ b/src/Messages/PurchaseRequest.php
@@ -3,14 +3,17 @@
 
 use Omnipay\Common\Message\AbstractRequest;
 use Omnipay\Common\Message\ResponseInterface;
+use OpenPayU_Exception;
+use OpenPayU_Order;
+use OpenPayU_Result;
 
 class PurchaseRequest extends AbstractRequest
 {
 
     /**
-     * @return array
+     * @return array<string, mixed>
      */
-    public function getData()
+    public function getData(): array
     {
         return $this->getParameters();
     }
@@ -18,51 +21,28 @@ public function getData()
     /**
      * Send the request with specified data
      *
-     * @param  mixed $data The data to send
-     * @return ResponseInterface
+     * @param array<string, mixed> $data The data to send
+     * @return ResponseInterface|PurchaseResponse
+     * @throws OpenPayU_Exception
      */
-    public function sendData($data)
+    public function sendData($data): ResponseInterface
     {
-        $headers = [
-            'Accept'        => 'application/json',
-            'Content-Type'  => 'application/json',
-            'Authorization' => $data['accessToken']
-        ];
-        $apiUrl = $data['apiUrl'] . '/api/v2_1/orders';
         if (isset($data['purchaseData']['extOrderId'])) {
             $this->setTransactionId($data['purchaseData']['extOrderId']);
         }
-        $httpRequest = $this->httpClient->post($apiUrl, $headers, json_encode($data['purchaseData']));
-        $httpRequest->configureRedirects(true, 0);
-        $httpResponse = $httpRequest->send();
-        $responseData = $httpResponse->json();
-        $response = new PurchaseResponse($this, $responseData);
+        /** @var OpenPayU_Result $response */
+        $response = OpenPayU_Order::create($data['purchaseData']);
 
-        return $this->response = $response;
-    }
+        $response = new PurchaseResponse($this, $response->getResponse());
 
-    /**
-     * @param string $apiUrl
-     */
-    public function setApiUrl($apiUrl)
-    {
-        $this->setParameter('apiUrl', $apiUrl);
+        return $this->response = $response;
     }
 
     /**
-     * @param array $data
+     * @param array<string, mixed> $data
      */
-    public function setPurchaseData($data)
+    public function setPurchaseData(array $data): void
     {
         $this->setParameter('purchaseData', $data);
     }
-
-    /**
-     * @param string $accessToken
-     */
-    public function setAccessToken($accessToken)
-    {
-        $this->setParameter('accessToken', $accessToken);
-    }
-
-}
\ No newline at end of file
+}
diff --git a/src/Messages/PurchaseResponse.php b/src/Messages/PurchaseResponse.php
index 3570c64..5f64c14 100644
--- a/src/Messages/PurchaseResponse.php
+++ b/src/Messages/PurchaseResponse.php
@@ -10,9 +10,9 @@ class PurchaseResponse extends AbstractResponse implements RedirectResponseInter
     /**
      * @return boolean
      */
-    public function isSuccessful()
+    public function isSuccessful(): bool
     {
-        if ('SUCCESS' !== $this->data['status']['statusCode']) {
+        if ('SUCCESS' !== $this->data->status->statusCode) {
             return false;
         }
         $redirectUrl = $this->getRedirectUrl();
@@ -23,19 +23,19 @@ public function isSuccessful()
     /**
      * Gets the redirect target url.
      */
-    public function getRedirectUrl()
+    public function getRedirectUrl(): ?string
     {
-        if (isset($this->data['redirectUri']) && is_string($this->data['redirectUri'])) {
-            return $this->data['redirectUri'];
-        } else {
-            return null;
+        if (isset($this->data->redirectUri) && is_string($this->data->redirectUri)) {
+            return $this->data->redirectUri;
         }
+
+        return null;
     }
 
     /**
      * Get the required redirect method (either GET or POST).
      */
-    public function getRedirectMethod()
+    public function getRedirectMethod(): string
     {
         return 'GET';
     }
@@ -43,7 +43,7 @@ public function getRedirectMethod()
     /**
      * Gets the redirect form data array, if the redirect method is POST.
      */
-    public function getRedirectData()
+    public function getRedirectData(): ?array
     {
         return null;
     }
@@ -51,10 +51,10 @@ public function getRedirectData()
     /**
      * @return string|null
      */
-    public function getTransactionId()
+    public function getTransactionId(): ?string
     {
-        if (isset($this->data['extOrderId']) && !empty($this->data['extOrderId'])) {
-            return (string) $this->data['extOrderId'];
+        if (isset($this->data->extOrderId) && !empty($this->data->extOrderId)) {
+            return (string) $this->data->extOrderId;
         }
         if (isset($this->request->getParameters()['transactionId']) && !empty($this->request->getParameters()['transactionId'])) {
             return $this->request->getParameters()['transactionId'];
@@ -65,18 +65,18 @@ public function getTransactionId()
 
     /**
      * PayU orderId
-     * @return string
+     * @return null|string
      */
-    public function getTransactionReference()
+    public function getTransactionReference(): ?string
     {
-        if (isset($this->data['orderId']) && !empty($this->data['orderId'])) {
-            return (string) $this->data['orderId'];
+        if (isset($this->data->orderId) && !empty($this->data->orderId)) {
+            return (string) $this->data->orderId;
         }
         return null;
     }
 
-    public function isRedirect()
+    public function isRedirect(): bool
     {
-        return is_string($this->data['redirectUri']);
+        return is_string($this->data->redirectUri);
     }
-}
\ No newline at end of file
+}