Cod Mobile Account Hacked Through Activision

I've been using my Cod Mobile account for years, and both my Facebook and Activision accounts were connected to it. So here's the deal, my Facebook connection is all good, but my Activision account has been hacked. I'm able to log into my account using Facebook, but unfortunately, someone else is also accessing it through Activision. It's really frustrating and concerning that I can't disconnect from the game even though it's been available for years. If there's someone who can help me out, I'll be happy. Otherwise, I'll have to delete my account and stop playing this game. Thanks a bunch.