Contract Cancellation

I've been trying to cancel my contract with cell c for about an hour now. I called cell c direct and asked them to put through cancellation but their phone keeps cutting. I spoke with Tumi, Leon and Salinda who gave a number 084 143 for cancellation but when I phone the number it says \the number you called does not exist". The network is poor and their employees are ***********. 70% of the time I don't get internet connection and my phones calls (incoming and outgoing) are dropped. People"