Click on this link to learn how to contact an app developer about problems running an app or problems restoring purchases. --> How to contact an app developer - Apple Support
If you cannot resolve the problem here's how to request an app or media refund from Apple (From: Request a refund for apps or content that you bought from Apple - Apple Support - see the article for more detail.)
1. Sign in to https://reportaproblem.apple.com
2. Tap or click "I'd like to," then choose "Request a refund."
3. Choose the reason why you want a refund, then choose Next.
4. Choose the app, subscription, or other item, then choose Submit.
If you were charged for a subscription that you no longer want, you can also cancel the subscription using the directions in this article --> If you want to cancel a subscription from Apple - Apple Support
If you still have problems, click here --> Choose your country or region - Official Apple Support Select your country, then a product.