Disclosure of personal & confidential information!

A friend of mine tells me he went to open an account at your branch in Dobsonville a few months ago. he coincidentally chose a pin code similar to the one I chose when I opened an account with you a year or so ago and was told he \can't use that pin code because it's used by Kabelo Mabeleng from Bramfischer."How on earth can FNB through their employee disclose such confidential information to third party"