Cant Log in to Account

I opened tiktok and tried to switch to my second account and it wasn't there so I tried to log into the account separately and tiktok said that it doesn't recognise the username or password but when I search up the account on tiktok its there but I just can't log in. I've tried contacting tiktok through their support website but it doesn't recognise the account username so I cant send the email. I dont know how to recover my account. What can I do?