The easiest way to request a refund is using the 'Your receipt from Apple' email.
Note: You can only request refunds for Mac (or iOS) apps you purchased in the last 90 days. You need to have a valid reason for the request-it's not a way to get free apps or trials-but if you accidentally buy an app, buy the wrong app, or don't get the app (wrong macOS version), you can get your money back. If you have a problem with a Mac app you purchased from the Mac App Store, you can request a refund directly from Apple. How to get a refund for Mac App Store purchases and in-app purchases isn't clear, but it is possible within 2-7 days!
