Refusal for me to cancel my contract

Cell is refusing me to cancel my contract that I took out last week. I received the modem it was delivered to me via courier on Wednesday the 9th of September 2015. In taking out my contract the consultant never advised me that I am applying for an open line I did however ask him if I may load airtime and he said no. He never stated that I cannot load airtime because it is an open line option and not a top up. I was contacted on Monday the 14th of September 2015 by a man names \Sakhela"he notified me that I have an open line that ran in access of R2100 I immediately disputed the amount and lodged a query under reference number:***. I was told in a SMS that if I do not hear anything from Cell C within 24 hours I should contact them on 084 140. I contacted Cell C back on the same day at about 10:45 in the morning to find out how long the query takes as I have an oppertunity to cancel the contract and within the CPA and that I do not want my time to run out based on this query. The consultant advised me that I have 7 days to do so and that the finalisation of the query usually takes up to 48 hrs. Till now my query has not been solved and Cell C won't allow me to cancel."""