failing to do what they get paid for

I am a Nedbank customer paying a lot every month for the service which I fail to receive! I have laid a complaint with nedbank online on 31 August and have received two calls assuring me that the problem will be sorted and still nothing has happened.... I am paying R125.00 every time a debit order returns because of insuffecient funds which would have been available had Nedbank done what they are getting paid to do.... They are taking my money time and time again for the wrong reasons and I am getting petty excuses every time... I am tired of the way my account is being handled and my money being taken when they are supposed to be protecting their customers money instead they are taking it! I cannot trust this bank after 5 years of being a customer with them..... I am moving my account to FNB if this problem persists and my money don't get refunded withing 48hrs!