Regarding unlinking my account to an email that is not mines

I have had a playstation account for some time, whenever I go into FC25, while I want to log in to the game with my online account active, I cannot as there is another email that is linked to the account which is not even my email at all. I've been having problems with this for the past couple of months and really need another way of unlinking this email address which is not mines off the actual PS4 account that I am logged into, is there anything I can do in regards to this?