How to get a refund for an app or in-app data item mistakenly purchased through the iTunes App Store for iPad or iPhone
Article SB1536, February 21, 2017
Obtain a refund via qualified request to https://reportaproblem.apple.com.
First, try to resolve any technical issue with an app or in-app purchase. Do not assume a given issue is difficult to fix or impossible, try working with technical support to resolve the issue.
Failing that, get an App Store refund by doing this:
1. Visit https://reportaproblem.apple.com ... this redirects to an Apple iTunes login page.
2. Sign In with your Apple ID.
3. Click the “Report a Problem” link beside the app or in-app items that needs refunding.
4. Choose the category “Problem is not listed here” and be sure to mention that you are asking for a refund because the item does not work as expected.
5. The Apple iTunes team (not individual app creating companies) determines whether or not to give a refund. They are generally willing to give refunds if a customer is not blatantly abusing the system and assuming they have not clouded the report of the issue with other categories of problem that may not be relevant to the refund request.