Cell c contract

What does one need to do to cancel a contract with Cell C?!!! I have been trying to do so since September. I have sent numerous emails, mostly not rep**** to. I am living abroad but they still debit me monthly. I was told I needed to pay a certain amount, which I did even though it was after numerous requests just to get it done. But still they deduct from me on monthly basis! To say I have had enough, is putting it mildly. I cannot call as I am not in SA so rely on email. All I want to do is cancel my contract, surely that's not asking too much. I have just been told, again, that I need to pay over R3k, it's madness!! Shocking service to say the least! Melanie