Contract upgrade mistake because of Cell C consultant

Cell C called us regarding a contract upgrade beginning of January. My mother and I went through the whole process over the phone with the consult and the deal was concluded. A few days later the phone was delivered. Month end of January when we received the statement we realise that the cell c consultant that was assisting us concerning the contract upgrade, did not upgrade the contract instead he started a new contract on a new package. Now there is two cell c contracts which is billing us enormous amounts of money per month which we did not budget for. When we contact customer service they say there's nothing they can do, we can only cancel the old contract which is not the outcome we are looking for because we dont want to change numbers. End of January and February we were billed R700, they sent statement this morning stating we getting billed R1300 end of March which is utterly ridiculous and disappointing.Initially we had put a budget for R350. This all started with a mistake that was made by your consultant and we are suffering for it. We have been with Cell C for the past ten years but after this we are definitely jumping ship to another network. So disappointing!!!!!!