Debit order issues

Debit order issues have become tedious issue with FNB, 3rd time now I have had a issue with a debit unpaid, each time I call into the contact center I seem to get a story. last time no one could even tell me why the issue occurred they just reversed my magtape unpaid. this time I am told even though there are funds visible they are pending. Staff at FNB have always been really helpful in trying to assist me but all this system red tape has become such a point of frustration to deal with.