Nedbank MFC *****ing money

I got harrassed by multiple calls saying my car loan was paid off when it wasnt, I asked for a manual debit order to be done so that I dont fall behind on payments, all of a sudden I am in arrears of my account when I have sent proof of payment being made every month. I have called, emailed and complained on the website and sent proof of the payment being made and yet extra money of R1500 was taken off my account still yet no one is getting back to me still!!