Unfair debit order practices

I've banked with FNB for some years now and i had not experienced a problem with them until recently. One of my debit orders failed to go through, despite money being deposited into my transactional account. The problem is that when a debit order bounces off, FNB charges you and the receiving company does the same. So I went to the branch and they reversed the charges, but they do not own up their mistake so that the other company can reverse their charges too. Hence because FNB declined a debit order, I'm subjected to paying hundreds of rands and the cycle goes on and on. This is proving to be such a costly banking service that i am receiving from FNB and I would like this to be corrected. It is indeed ******ing money out of clients and it just cannot be!