Fix or refund, please? – Cleartune Review

I just purchased this on a recommendation from a fellow violinist. I’m on iOS 12 on my iPhone 5s. The pitch pipe feature does not work at all. I checked settings, restarted my phone, and even removed the app and reloaded it. Nothing. Can you please tell me how to remedy this problem or give me a refund? Follow up: After 3 days of waiting for a response here in the App Store, I decided to try to contact the developer via their website, but all I got after typing in my message and hitting "send" was an "internal server error" message. so I called Apple support, and Apple issued a refund. Thank you Apple for rectifying the issue.
Review by K.P.G. on Cleartune.