Steam account is linked to the wrong EA account how to unlink?

My account was hacked and is now linked to an EA account that is not mine. How do I unlink the account? I can't play The Sims 4 because it always says "There's been an error" even after I try to reinstall the game. I know that if I want to unlink it, I have to contact customer support, but I don't know how to contact them. please help me