Cellphone Banking and Notifications

I changed my account number to a new account no and I have not been able to register for email notificatuons and cellphone banking since. I have been to 3 different branches to register for cellphone banking but evertime it's not happening. I still use the same cellphone number and the old account number is the one existing on the phone. I have asked for my details to be updated to the new bank account number but with no help. What do i do now to register my new account?