I know my GC Id but can't log in
Hello.
I had my apple ID with a yahoo email, yesterday I did the process to change the email to gmail.
But know I can't log in into my Game Center Account. I know all the answer to the security questions and everything else as it is my account, but I can't seem to enter the older Game Center ID.
I had created other Game Center ID with a few different emails, so I might have crossed emails with GC Id or something, please help. I buyed games and other stuff but know there's nothing in my history.
iPhone 5, iOS 9.3