Annoyed MTN customer

My contract for the 2 years was ending. They called to ask me if I would like to upgrade. I said no, I would like to be on prepaid. The female sales rep said I could go onto a data package where I need to just phone a month in advance to cancel. Now I have phoned a month in advance and the male rep said I will have to pay R505 to cancel the contract, but its for data, not a phone. He then said I need to go into MTN to cancel, get a ref number, phone MTN again with the ref number.