NEDBANK MFC INCOMPETENCE

I have purchased a vehicle with MFC for 12mths now and I then started experiencing problems on the 12th month. Suddenly my debit order goes off before my pay day. As to who, why it has been changed I don't know. What I know is that I have been receiving calls from their agents to say my debit order didn't go through since Aug it's now Oct. This is totally insane. I wanty debit order rejections paid back with urgency coz I will not be held liable for Nedbank's incompetence. This has cause my unnecessary stress and unnecessary bank charges