Unlink account.

Hi I did just buy Fc25 and after I start playing it tells me about linked account and the account that’s linked with my psnID is very old email that is school mail and know deleted, here is the problem I did everything eventually I find the email and logged into forgot password and I could reset the password with my other email that I made with Ea mail but as soon go back and I login and the password Directly changed it’s so fast that I don’t think it’s I human I believe its AI that’s changing the password I really need help I have contacted EA help supports  the asking for questions that I have no idea about the account and all I want is just so the account is unliked from my psnID. And the phone number dose not exist anymore.