Unhelpful staff who do not assist clients

Have had 2 American Express credit cards which have been paid up. However just prior to them being paid up I requested a detailed copy of these two accounts as I needed to know balances for final payment. Monthly payments were made to these two accounts consistantly through FNB to Nedbank. When I received these copies it was noted that there were numerous payments not reflecting on their summaries. On speaking to Lance Williams and Ms Britton - Supervisor and sending copies of these payments to Nedbank they have stated that they will not/cannot trace these payments. With numerous payments not reflecting on my summary of account indicates that there is a credit balance on my accounts and needs to be brought up to date. Any monies overpaid to Nedbank have to be repaid to me.