Terrible and rude client services

I've been requesting a paid up letter at Nedbank since the the beginning of the month,I was told at the branch to change my cell phone number because the one I used was not in their system went to the branch changed my number called them back they keep on giving me a run around I'm very extremely disappointed ,all the consultant have not been helpful ,today I called again asking they dropped a call on me ,poor service delivery,now I'm stuck because I'm trying to buy property