You can delete your account and everything in it from inside the app:
CoinBell → Settings → Delete account
The app keeps working after deletion. It simply goes back to working without an account, the way it does before you sign in.
Deletion is immediate and cannot be undone. Backups are rotated out within 30 days.
Email lookmetech@gmail.com from the address you signed in with and ask for deletion. We will confirm once it is done.