My old account is locked because my old phone is no longer working can anyone help please.
Same here. Original account is locked due to the authenticator.
Going to have to go to T-mobile because the old phone number the authenticator originally used is no longer in service.
The only way to handle that is to contact Blizzard directly through a ticket. Be prepared to prove you are the registered account holder before Blizz will remove the Auth and old phone number.
https://us.battle.net/support/en/help/product/battlenet/316/977/solution
You may also need the info on providing a Govt issued ID.