Tik tok account problems

Got randomly logged out of my account. When I try to log back in it doesn’t work, what happens is it just makes me a new account. Even though I’m logging in with my phone number and email and all that from my old account. Weeks later I stumbled across my old account while scrolling. It has a different user name. It used to be “anthonyflok”

Now it’s “968306yflok”. So I went to log in again, used that user name and then type in my password and it just logs me into my new account… not really sure how I can log into an account if I don’t have the right username. I have tried to recover my account, change the password etc… doesn’t matter what I do I can’t log into my old account even though I have the username. Anyone have this problem before?