Debit order reversal

I have a debit order with Cash Convertors, MetroFin and Sharp Cash loans. I have then requested Debt review and they are negotiating with the companies in concern. But then to my surprise, the debit orders went through and FNB does not want to reverse them for me. The above mentioned loans companies instructed me to go to FNB but then the consultants there are very rude and does not even want to check on the system. They just said it's impossible. How am I supposed to trust a bank that cannot help me?