Line Cancellation September 2017

I requested to cancel my Telkom line last year September after my WiFi wasn't working for 3 months and my line was physically cut. I sent all documentations to them, i phoned and was put on hold for hours on end. ... Only to receive a bill now for R15000 after requesting proof that it was cancelled and being put on hold for hours. I finally got hold of them and now my accounts is being looked at, it has been a week and no response. How can such a well known company just not respond to their customers. Lucky for me i have screenshots of being on hold for hours with Telkom and all emails dated back to last year. This is honestly just unacceptable.