Sign in issues

My ipad where I installed freenotes on suddenly shut down and wouldn't turn on. I just sent it to the shop but it's not looking good as they said my ipad is quite old and outdated so the chances of recovery is low. I installed this app on my phone and tried signing in using the same email but it says "users who have previously entered an email, please sign up using the same email before logging in"

When I went to sign up instead, it says " sign up failed, the email address is already in use by another account".

Is there any different way to log in? or any way to get my account back? Please help!!! Thank you 🥹