Unknown EA account is linked to my steam account, help

I wanted to download The Sims4, but as I tried to link my new account to my own it said my steam account can't be linked to my EA account since I already have an EA account linked to my Steam's. I know for sure this account isn't mine, and I can't seem to find a way to unlink it - since you can only unlink the steam account from the EA account from the EA account (confusing, I know) but in any way I could really use some help and tips on how to solve this problem, since I couldn't find anything in the steam support. I'm desperate and the thought of someone else's account linked to mine is freaking me out, so if anyone knows what I can do about it please comment🙏

P.s. I barely know tech so the tags may be unrelated since I had to put one, I'm not sure if it's something people here could help but I hope it is relevant and counts as tech problem 😔