Hi,
You can get a refund by following this process:
- Visit https://reportaproblem.apple.com logged in with the Apple ID you purchased the app with.
- Find the app in the list or search.
- Click "Report a Problem".
- In the dropdown, choose "Item opens but doesn't function as expected".
- Click "Submit".
Your refund will be processed immediately. Let me know if you have any questions.
Best,
Dan