Worst service provider ever!

I took out 2No data contracts with Cell C @R99pm each(reception was poor). I then moved into a flat with Wi-Fi-Telkom (reception was great), so I attempted to put in notice to cancel @the end of the Cell C contractual period- which they denied as 'notification could only be sent +-60days prior to the contract end date'. As I though I would, I forgot about these usbs, until I got a surprise debit of approximately R700 from Cell C. I spent \hours"(with Cell C customer care) trying to establish the problem. Eventually I'm told that the small print on the back of my contract allows Cell C to increase my monthly debits @the end of the original contact period- without any notification and there is nothing they can do to assist. So again I try to cancel but now I get told that they require a calendar months notice to cancel& I will get debited yet again @the increased rate. After much fighting Cell C agrees they will refund me a portion of the second increased debit"