**** and poor customer service

I am not happy with your service u have paid off my remaining balance which was 3041,89,I have tried many times sending you emails to acknowledge my payment no one has done that not even a simple email, I requested a call no one tried to call now I have received a statement stating that I owe R500 which is the reason I wanted you guys to call me to explain what was that for , I never skipped my payment and I paid the balance in full, my monthly payment was R405 so why do u have to pay extra amount? Are you telling me I was penalized for paying off the debt before time hows that making sense ?