All purchases are processed by the store where you downloaded the game from, so please contact the store's customer support to request a refund.

If the purchase was made on an iOS device:
Go to the App Store Support page, select the link for "Get help with your purchases and refunds," and find the option that best suits your situation.

If the purchase was made on an Android device:
Go to the Google Play Help page or Amazon Appstore support page and follow the instructions for your device.