Telkom line cancellations

I cancelled my ADSL in May 2017, but retained the line itself to make and receive calls. We sold our house and I completed and emailed the documents to cancel the line in October 2017 - termination as of end November 2017. To date, that line has not been cancelled. There is no area dedicated to issues with line cancellations and you are not issued a reference number when speaking to billing. They assure me that they will escalate it, but every month I am billed for a line that I have cancelled. On a few occasions I have received a call after an escalation to make an appointment to install a line for me (?). The problem is that I now live in a smaller city and have to make use of Telkom for ADSL - fibre is still a dream. If I refuse to pay for the line that I cancelled, Telkom merely suspend my current service which I need. I am horrified at the terrible customer service and the lack of a process within the company to resolve issues like this. I should at the very least have a reference number which tracks the fact that there is a dispute between Telkom and I and that details the events. I have no idea how to get this resolved, how many times must I phone just to go round in circles?