Hacked my account on fifa

I'm currently playing FIFA Mobile or FC Mobile. I'm still playing at this moment, but someone else is playing with me on the same account. I've tried everything to remove this person from my account, but I don't know how they can still be playing. I've unlinked Facebook, Google Chrome, and everything else, but the problem persists. I need a way to remove them from my account. I'm so frustrated with FC Mobile's security; it's very weak. I don't know how they even got into my account. I haven't shared any of my information with anyone. I hope you can solve my problem as soon as possible. Thank you, and I hope you can fix this issue. It's a very serious security vulnerability. I wish you success, and thank you again.