Questions, problems, or anything that looks wrong.
Email daotunghb@gmail.com. Please include your iOS version and what you were doing when the problem happened — it makes a fix much faster.
On your device, and only there. The app has no account and no server, and makes no network requests at all. Nothing you log is ever sent anywhere. Purchases are handled by Apple, which is the one exception — and no log data is involved in one.
This also means the data is not backed up by us and cannot be recovered by us. It is included in your encrypted iPhone or iCloud device backup.
Profile → Privacy → Erase All Data. This permanently removes the database and every stored preference. It cannot be undone.
Manage or cancel in the Settings app: tap your name → Subscriptions. Cancelling stops future charges; anything you have already recorded stays readable in the app.
Restore a purchase on a new device from the subscription screen inside the app.