Profile changes with out communication to clients

FNB upgraded their system and in the upgrade decided to change the username I have used for the last 5 years without any communication. When I called the call centre, they were not aware of any changes to the system, yet my e-mail address was now defaulted as my username on my login. Why change it without any communication. It is very risky to have your login as your e-mail, secondly it took me 4 calls to the call centre to figure out why I cannot access my account that I have had for 13 years.