Worried someone has access to my Apple ID after being locked out of the account

I’m worried someone has access to my Apple ID and iCloud. I’m locked out of my account and can get the code sent to my phone to reset the password but nothing can be done. Why is this ? I went into gmail and it’s been proven he was a trusted device on my Apple account. How can I regain access if I’m locked out of it ? What if the code was sent to his phone and he can break into my account ?