Telkom refuses to cancel my non-existent line

Telkom is useless!!!! I send through my cancellation on 23 March 2018 and am still being billed. I am constantly on the phone with Telkom, however nobody seems to be able to finalize the cancellation. The reason for my cancellation is that my line stopped working in Feb 2018 after being damaged in October 2017 already. Telkom refused to do fix the physical line even though we continued logging calls (they just closed these calls saying it is resolved). When the line died We had enough and cancelled the line. The old line was removed, however I am still being billed and no refund is being processed.