I think my account is being accessed by someone else and I want to stop this

I got my account from someone permanently and linked my account to My personal Facebook and my Gmail but for a few days I've been noticing some things off about my account such as I didn't unlock Zidane event second chapter and it's not unlocked also someone played a h2h on my account after the Division Rivals reset and random players keep getting added to my watchlist but now I've had a firsthand encounter of someone logging into my account I attached the Screenshot of it below I have contacted in-game support they gave me a few ways to fix it I tried all of them and its not working they told me to turn on two factor authentication on my FC mobile id but I don't know how to do it

[Images removed - Admin.]