An EA account was already linked to my Steam account. And i want to unlinked it

When i tried to play EA games through Steam but it's already connected to an EA account without my knowledge. BTW my Steam account was hacked once, i think this was the time they linked it. My question can i unlinked it? I tried contacting steam support but they couldn't help with third party accounts. I want to unlinked my Steam account and the hackers account. The games i was trying to play were Battlefield 1 and Farcry 3. Attached are the accounts that are linked on those games