diff --git a/subscription/DTO/SubscriptionCarrierProviderData.php b/subscription/DTO/SubscriptionCarrierProviderData.php
index 6d653a2e5..0b755ac74 100644
--- a/subscription/DTO/SubscriptionCarrierProviderData.php
+++ b/subscription/DTO/SubscriptionCarrierProviderData.php
@@ -18,9 +18,9 @@
 
 class SubscriptionCarrierProviderData
 {
-    /** @var int */
+    /** @var string */
     private $mollieCustomerId;
-    /** @var int */
+    /** @var string */
     private $mollieSubscriptionId;
     /** @var int */
     private $subscriptionCarrierId;
@@ -28,8 +28,8 @@ class SubscriptionCarrierProviderData
     private $orderId;
 
     private function __construct(
-        int $mollieCustomerId,
-        int $mollieSubscriptionId,
+        string $mollieCustomerId,
+        string $mollieSubscriptionId,
         int $subscriptionCarrierId,
         int $orderId
     ) {
@@ -40,17 +40,17 @@ private function __construct(
     }
 
     /**
-     * @return int
+     * @return string
      */
-    public function getMollieCustomerId(): int
+    public function getMollieCustomerId(): string
     {
         return $this->mollieCustomerId;
     }
 
     /**
-     * @return int
+     * @return string
      */
-    public function getMollieSubscriptionId(): int
+    public function getMollieSubscriptionId(): string
     {
         return $this->mollieSubscriptionId;
     }
@@ -72,8 +72,8 @@ public function getOrderId(): int
     }
 
     public static function create(
-        int $mollieCustomerId,
-        int $mollieSubscriptionId,
+        string $mollieCustomerId,
+        string $mollieSubscriptionId,
         int $subscriptionCarrierId,
         int $orderId
     ): self {
diff --git a/tests/Unit/Subscription/Provider/SubscriptionCarrierProviderTest.php b/tests/Unit/Subscription/Provider/SubscriptionCarrierProviderTest.php
index caec266d9..3250d24cb 100644
--- a/tests/Unit/Subscription/Provider/SubscriptionCarrierProviderTest.php
+++ b/tests/Unit/Subscription/Provider/SubscriptionCarrierProviderTest.php
@@ -66,14 +66,14 @@ public function testItSuccessfullyProvidesData(): void
         );
 
         $result = $subscriptionCarrierProvider->get(SubscriptionCarrierProviderData::create(
-            1,
-            2,
+            'test-mollie-customer-id',
+            'test-mollie-subscription-id',
             3,
             4
         ));
 
-        $this->assertEquals(1, $result->getCustomerId());
-        $this->assertEquals(2, $result->getSubscriptionId());
+        $this->assertEquals('test-mollie-customer-id', $result->getCustomerId());
+        $this->assertEquals('test-mollie-subscription-id', $result->getSubscriptionId());
         $this->assertEquals([
             'metadata' => [
                 'secure_key' => SecureKeyUtility::generateReturnKey(
@@ -113,8 +113,8 @@ public function testItUnsuccessfullyProvidesDataFailedToFindOrder(): void
         $this->expectExceptionCode(ExceptionCode::ORDER_FAILED_TO_FIND_ORDER);
 
         $subscriptionCarrierProvider->get(SubscriptionCarrierProviderData::create(
-            1,
-            2,
+            'test-mollie-customer-id',
+            'test-mollie-subscription-id',
             3,
             4
         ));
@@ -152,8 +152,8 @@ public function testItUnsuccessfullyProvidesDataFailedToFindSubscriptionProduct(
         $this->expectExceptionCode(ExceptionCode::ORDER_FAILED_TO_FIND_SUBSCRIPTION_PRODUCT);
 
         $subscriptionCarrierProvider->get(SubscriptionCarrierProviderData::create(
-            1,
-            2,
+            'test-mollie-customer-id',
+            'test-mollie-subscription-id',
             3,
             4
         ));
@@ -191,8 +191,8 @@ public function testItUnsuccessfullyProvidesDataFailedToProvideSubscriptionOrder
         $this->expectExceptionCode(ExceptionCode::ORDER_FAILED_TO_PROVIDE_SUBSCRIPTION_ORDER_AMOUNT);
 
         $subscriptionCarrierProvider->get(SubscriptionCarrierProviderData::create(
-            1,
-            2,
+            'test-mollie-customer-id',
+            'test-mollie-subscription-id',
             3,
             4
         ));