Unlinking an EA account that isn’t mine

Over a year ago, I allowed somebody to use my Xbox. They put their EA account on my Xbox now I can’t link my own because theirs is there. I no longer have contact with this person. How can Ito use my Xbox. They put their EA account on my Xbox now I can’t link my own because there’s is there. I no longer have contact with this person. How can I get it unlinked from my account