How? I still get a text to my physical phone with the active number being ported and use the code supplied to initiate the process. Somehow making them change

How? I still get a text to my physical phone with the active number being ported and use the code supplied to initiate the process. Somehow making them change my contact details would just end up with the bills being sent to the wrong place, if you still have paper bills and don't have it automatically paid or goes to a digital mailbox.