Making figures up

I was handed over to MBD by Vodacom, MBD claims that I owe R 1309.65, they also claim that they have had no response from me when in fact I have sent no less than 3 emails requesting they send me a statement as it is literally impossible that I owe R1309.65 on an account of less than R800. Even Vodacom on Transunion has stated that I owe this amount. I am more than willing to pay an account however, I need to know exactly what I am paying for. They can't just make up random amounts and expect people to pay with a smile on their faces. I have even gone as far as to request a statement on their website on two occasions but no response has been given.