Who has access to this data?

Yesterday a call centre agent from Standard Bank phoned me to upgrade my current account to a different level. <br> <br> Whilst I have no problem with the call, I am extremely distressed that he read out my account number, in full, to me. I do not believe that call centre agents should have access to this information - it's obviously on their systems and available to all! I don't even know if this was a real Standard Bank employee or whether it was someone trying to get information from me to access my account.<br> <br> Whatever happened to only giving agents partial information - such as the last four digits of your bank account?