Billing error

I am very unhappy with multichoice. I called them to stop internet and they told me that I should pay plus minus R270 something and I paid it and they disconnected and my balance on 13th of February was R0. Today hen I call tto reconnect they said I owe R972.98. I told them that I don't owe that money and the first consultant said it was the system error and it will be fixed within 48 hours, whereas the second consultant said I need to pay what the system is telling her and there was no error. I want multichoice to fix this error and reconnect me or I will escalate it.

I have been their customer for more than 17 years now.