How do I request a refund?
If you accidentally purchased a subscription, you can request a refund from Apple on reportaproblem.apple.com
The exact process is described on support.apple.com/en-us/HT204084
Attention
Please note that all purchases on the App Store are processed by Apple.App developers have no access to the purchase data and can neither change a customer’s purchase nor trigger any refunds.
We do our best to assist when our users have problems with their purchases. However, often all we can do is refer to the Apple App Store Support, unfortunately.