[2021] (PC) My Activision email was changed by someone else, how do I fix this?

I got an email that says the email on COD account was changed. It says if I didnt do this to contact their support, but all it told me was "make a new activision account then link all platforms to that account" Then it says if the request is valid, the new account i create will no longer be accessible? So my new account wont be accessible? I checked my email by loading COD and checking my account settings and it has in fact been changed by someone else. Has anyone had this happen before and how did you solve it