Contract was cancelled but still being billed

I am extremely outraged at Telkom. I was unable to use my internet from January-March 2015, I was still billed even though I couldn't use it, and their technicians who came a month late told me they couldn't solve my issue. My contract was cancelled and a complaint logged for a refund of all the money I had paid for January and February, after which I stopped paying because I was being ******, paying for something I could not use. I am still being billed and the amount is escalating, I refuse to pay it. This needs to be sorted out TODAY!!! The manager in Claremont cancelled the contract and the complaint and case was logged by Zianda at the call center, whom has yet to get back to us after two months. My reference number was ***9. I will take this matter further if it is not resolved.