I have a contract phone and only one bliz account

I’ve had my blizzard account and pay monthly contract mobile for a number of years now and yet I am still unable to add my mobile number to my account to play a game. My location is correct, I only have one blizzard account so my number is not already in use and as I have had this number for probably near a decade (and used it for other 2fa) I can’t imagine why it would be an issue now.
I know I am just another person in a long line of complaints but surely this should have been sorted some time ago? I’m reading posts from 2 years ago with the same issue!!

Is there no other way we are able to verify our accounts??