Write to [email protected] — a real person reads it, usually answering within two business days.
The app version (Settings → the version line at the bottom), your phone model, and what you expected to happen. In Settings there is Send feedback, which attaches the app version, the platform and the in-app log to the message — it tells you exactly what is being sent before it goes.
That is deliberate. Below a confidence threshold the app shows an honest "not sure" screen and never asks for money for a guess.
Only while a test is running and the screen shows it. There is no background listening of any kind.
Recording and the spectrum work on anything. Verdicts are trained for specific appliance families and the app tells you when it is outside them.
Purchases are handled by the store, so refunds are requested there: on Android through Google Play (Order history → Report a problem), on iOS through Apple (reportaproblem.apple.com). If a refund is refused and you believe the app is at fault, write to us anyway — we would rather refund you than argue.
What the app does with data is written out in full on the privacy page.