My address was updated without me knowing about it

On the 08 Feb 2017 I was opening a business account at an FNB branch, and when I had to confirm the card delivery address I then noticed that address: 13 Korhaan Street Rant En Dal Krugersdorp Gauteng was linked to my profile / ID number. I don't know the mentioned address, and I've never stayed at this address. I then asked my private banker to investigate what happened and he confirmed Nondumiso Ngcukayithobi from home loans department updated this address. I then requested that she provide formal reasons why she updated my address without my knowledge, to date I still don't have the reasons behind the address change. My private banker suspect that Nondumiso might have left the bank, because he can't get hold of her. My biggest concern is that this address update might be linked to some ********** / ******* activities that might have happened when she changed this address. I demand the address update reasons, and confirmation that no ******* activities happened in this regard.