Annoyed customer

I opened my bank account 2008 at FNB in Johannesburg and I have been using it the account till to date. I relocated to Cape town in 2016. I don't have any accounts except my bank account. for the past years I have been going to FNB to update my address using the UNISA's statement as I don't have any accounts and yet they are refusing to change my address. I'm really annoyed at their unnecessary process and its not like I'm applying for a loan or anything, I just want to change my address.

They don't want any affidavit, they said my land lord must fill documentation. I have been explaining to them that my landlord is always in Johannesburg. I really don't understand why do they need to make such a big deal about this because I have proof. I just can't wait to change my account and bank with another bank. FNB can not tell me that they can't track my transactions.