Do not take a contract with Vodacom

I wouldn't advice anyone to take a contract with Vodacom as it is a ****. I had a contract with them for about 12 months, in December I requested a settlement quotation which they forwarded to me with the instructions to follow after paying the required amount to settlement the contract. I paid the required amount within 14 days as specified on the contract and forwarded proof of payment together with the required amount. Sent few email before the contract was successfully canceled. I further received an email stating an outstanding usage costs would be debited in the following month which I understood. I was on capped contract which I was paying R840. I had expected them to debit that amount to my suprise R4892 was debited without any explanation, tried calling the customer service to no avail sent an email no response.

Can someone please explain to me why such an amount were debit or reverse my money as soon as possible.