Paying for something I don't have

This morning Cell C has debited my account for an amount of R259.96 which was not an amount I Authorised. <br> When upgrading my contract of the same number, I have agreed for a debit of R130.00p/m as per contract and my data,min and sms will be loaded onto my old number and I would be given a new device. When I called Cell this morning, I was informed by an agent that I have 2 lines with Cell C, one being an 084.... which I am aware of and currently using as well as a 074..... which I have no clue about and don't even have a sim card for that number. I was put through to the retentions department which resulted in the Call ending before I reached Retentions. So I called back and went through the same process and the same result of the call ending...so I called 084143 and still no Joy of speaking to anyone. Should I now sit at work with my boss around calling Cell C the entire day to resolve their mistake. As a Client I think this is not fair. If this issue is not resolved within 5 hours. I would gladly like to ask Cell C to Cancel my contract and fetch they device and reverse all payments on the new contract including bank charges that I the Client have incurred.