UNAUTH ADDRESS CHANGE ON MY ACCOUNTS

Shocking service from FNB. My address on my accounts were changed without my request or authorization and NO ONE is able to get to the bottom of this. I have been transferred from pillar to post and been cut off countless times in the process, and I still have NO ANSWERS! When asked to speak to a Manager, I am told I need a reference number for the complaint, which was clearly not logged by the 5 consultants I have already spoken too and then conveniently I get cut off again without any help or assistance. I have reached my limit now with FNB. How is a change of address allowed when I have to submit my ID and proof of residence when these changes are made, but somehow someone has access to my personal details and changes my address? I need answers and I need the address on the statements to show the correct address for emigration purposes.