Someone has changed my trusted phone number, now my Apple ID is locked, please help me to unlock my account.

Someone has changed two factor verification phone number of my Apple account. Now, my Apple account has been locked because of security purposes so I cannot log into my account can’t even log out. I’m in serious trouble, I don’t have the access of the number they have set as my trusted phone number. In this circumstances, please help me to recover and unlock my Apple account. It’s my 9 years old Apple account. And I had been using 4 iPhones of mine with this single account. If I don’t get my id back then all these devices will remain useless. HELP ME !!