diff --git a/src/Message/FetchTransactionResponse.php b/src/Message/FetchTransactionResponse.php
index 4676f7b..9db5cd6 100644
--- a/src/Message/FetchTransactionResponse.php
+++ b/src/Message/FetchTransactionResponse.php
@@ -93,8 +93,8 @@ public function isExpired()
      */
     public function getTransactionReference()
     {
-        if (isset($this->data['id'])) {
-            return $this->data['id'];
+        if (isset($this->data['transaction']['transactionId'])) {
+            return $this->data['transaction']['transactionId'];
         }
     }