Continuing theft

I posted here a month ago that I had cancelled my Telkom service on 30 November 2015, but that I was still being billed. I was contacted by someone called Gezia, who asked me to send her the cancellations forms, which I did. She did not respond, and lo! and behold I've received another bill today. Telkom are nothing more than *******, because it is not in their interests to cancel any service. It's even worse because one is not allowed to call the cancellation department.