Charged twice for a purchase

For Apple Store purchase:

1. Go to reportaproblem.apple.com. 
2. Sign in with your credentials.
3. Click on the "Report" or "Report a Problem" button next to the item that you want to request a refund for.
4. Include the reason for the refund request.

For Google Play purchase:

1. Go to https://play.google.com/store/account > "Order History" and find the order you want to return.
2. Select "Request a refund".
3. Choose the reason for the refund request.