Unable to cancel my account

I have been trying to cancel my landline since June 2018. Here we are in 2019 and I am still being billed for a line I do not use. I have submitted many cancelation requests as well as multiple disputes and telephone calls, but nothing changes. I now "owe" nearly R2000 that I refuse to pay because I have requested so many cancelations.

This is why your company is failing, you cannot get the most simple aspects of business correct, never mind the complicated parts like providing a competative service.