Difficulty in cancellation of contract

I had a data contract with CellC - 24 months at R 99-00 per month for 2 Gb data. According to the contract conditions, they were supposed to warn me between 40 and 80 days prior to the end of the 24 months. This was not done. Thus I was too late to give the 30 days notice of cancellation before the end of the 24 months, and was billed R 279-00 for the month of April. I tried on 2015-03-26 to fax my intention to cancel the contract to CellC's fax number on their website. This did not go through after numerous attempts.<br> On 2 April I went to CellC at the Mall@Reds to do the cancellation. They phoned the call centre and I spoke to the person handling the call, stating my wish to cancel the contract. A reference number for this call was not given to me. At the end of April I received a further account for R 279-00, although I stopped using the CellC's data service. I again approached the office at Mall@Reds, the manager phoned the call centre, I again reiterated that the contract should have been cancelled at the end of April, according to my previous communication. This time I insisted on a reference number. The R 279-00 is still being deducted from my bank account!!<br>