Note: Every app purchased from Mac Apple Store not refunded but if you have a good case, they will return the amount. One more important thing, it will only applicable to app purchases made in the last 90 days.
I will show you how to request a refund from Mac Apple Store through the entire process step-by-step.
1. Click on the link https://phobos.apple.com/purchasehistory
2. Open your purchase history directly inside iTunes.
Open iTunes on your Mac and choose Store – View Account. Next click See All under the Purchase History.
3. Click the Report a Problem link available against recent app purchases.
If the App is not listed in your recent purchased list, click the little grey arrow to expand the order that contains your app and click the Report a Problem link.
4. Now it will redirect you to reportaproblem.apple.com website.
5. Here you specify the reason for requesting a refund for the Mac App. You are also likely to choose “I didn’t authorize the purchase” or “Item functions but doesn’t work as expected”.
6. Click on submit.
Now you see a “Request Refund” button. click on it and refund will be processed in 5 to 7 days. In case, you didn’t see “Request Refund” button, someone from Mac Apple support team will contact you within 48 hours via the email address associated with this Apple ID to solve your problem.