Mysterious Email Address being added to my Accounts Security.

I'm not sure who to contact, and really cannot find where to contact someone about removing a mysterious address that keeps adding itself under my accounts security. I've tried removing it a month ago or so, gave the right information to get it removed, but it never got removed. I even linked my account with another of my email address to retrieve any information if it gets hacked, and now both have this account under it. It says to wait a month and it will be removed, I even have my mobile number for security reasons, but it doesn't help at all. Like I said before it was supposed to be removed long ago but it never did. I really would like some help on how to skip this monthly wait because there is no way the account that keeps adding itself is mine, and can provide even further proof to confirm my account, like I said the unknown email even added to my other account after linking it.