Horrible service from customer service and no feedback.

I had 2 contracts at Cell C. I called Cell C and asked them what the current settlement amount was. They gave me the amounts, I made the payments and went to a Cell C shop with the proof of payments. A nice guy helped me there, we closed the one contract and tried to keep the other one open. Keep in mind, I paid the amounts that they gave me. So the one contract was closed but now they are telling me that I need to pay a further X amount that is still outstanding. This is completely and utterly absurd because I paid the amount they gave me the day I called them. I just spoke to a lady at Customer Service. I explained to her what had happened. She said I can e-mail the statement they sent along with the proof of payment. I asked her for an e-mail address and she then proceeded to give me and e-mail address that does not exist. I have been trying to get answers for about a month now. And it seems like theybare just adding amounts after I have paid up the contract.