Bad Service at MTN Mall at Reds

Yesterday my son's Nanny went to MTN Mall at Reds, to do a SIM swop after her cellphone was ******, When she got there, Patience from MTN told her that she needed 3 months bank statements and also needed to buy a prepaid package (card) even though she had previously already obtained a prepaid card from another MTN shop. When the Nanny got back from the bank, she was helped by another MTN agent who told her that she didn't need the bank statement, neither had she to buy a second prepaid card. He promptly assisted her and sorted out the problem.

I wonder what part of customer service and customer retention Patience doesn't understand.