Re: someone linked my EA account to their steam what do i do?

@a24zxc5411011abxput two factor authentication on and contact the EA Customer support.

https://help.ea.com/en/contact-us/

When you turn on the two-factor authentication it should give you the option to sign out of all other devices. That will sign the person out of your account. They won't be able to access it again without the code from two factor authentication. 

You might want to change more than just your EA account password. If they got your EA account password it's possible they have access to email, social media accounts and so on. It might be a bit paranoid but you're better off playing it safe than sorry.