Nedbank no accountability

I have been a client of Nedbank for many years.My whole life is at Nedbank(for now).I am aware fees etc are charged if an account is overdrawn or if debit orders get returned.....End of February Nedbank cr card department erroneously took off 2xinstalments....This resulted in my account being overdrawn.I had to call around and get the department to fix the problem which they did..Christene Page was friendly and went out of her way to rectify their error. Unfortunately their error resulted in my Homeloan which is also with them to result in my account going into a negative. They charged me honorary fee for the HL and another transaction.Calling their credit division whom was part of the fixing of the cr card error...I am still liable for the honorary fees....how am I the client liable for a fee that resulted due to their error.....Service and accountability is clearing not in their mission statement......