Worst assistance received

I took out a contract thus year with telkom at an agreed amount..in August my bill was higher than the agreed amount. When I called into telkom the guy explained what the reason was for stuff that was activated two years ago and I agreed to pay and he advised he would close it and not be billed again. At the end of September the bill was again higher, when I called to query the woman said the guy didn't close it and I must pay again and she will close it. I refuse to pay and when I told her this she said there is nothing they can do, spoke to another agent and the same thing..they didn't even bother to log a query for me for someone to call me or anything just refused to help me out. I have canceled the debit order and refused to pay until I get this sorted out. I cannot pay for telkoms negligence. They are the worst when it comes to customer service.