Unable to Access My Tandem Account – Reinstalling App Blocks Login

I’m unable to log into my Tandem account after accidentally deleting the app. When I reinstalled it, I got a message saying I had a “different login method for this account,” preventing me from accessing it. I even tried creating a new account, but I received a message that they'd get back to me within 7 days. It's been 14 days, and I've had no response. I rely on Tandem for language practice, and this delay and lack of access are extremely frustrating. Tandem, please help resolve this issue so I can regain access to my account promptly.