Telkom refuses to cancel my line and owe me over R7000.

I cancelled my line in November 2017. I had to send through various documents and speak to numerous people to convince them to eventually cancel my line (which had stopped working several weeks before). I have just been informed that my line is still active well over a year later. I have taken a look at my bank statements and can confirm that I have been charged an accumulated amount of over R7000 for a cancelled line.