Worst Cancellation Services

So I get a call from the Telkom sales department. An agent tells me about this LTE modem for R100 p.m, I mention to her that I already have an LTE router with them. She then advises me that the modem I currently have is a on a month to month contract (Contract Completed) and that it can be cancelled with no cancellation costs. So of course I'm interested in the new deal as opposed to my current one. She activates the new modem on my account and it's delivered to me the next day. I complete the cancellation form for my modem ("Completed Contract") and sent it to them in Mid November. So they claim it takes up to 21 working days to have it cancelled, to date I had to call then 3 times already after this period only to hear that the matter has been escalated - all 3 times. I especially mentioned to the last agent that I will not be calling in again and requested immediate feedback - that was a week ago and I have heard nothing as yet, no feedback whatsoever. At this point I feel like cancelling everything with Telkom, I have been loyal for over 6 years, but this is the level of service I receive. For a company of this size I expected much more. Now I wasted even more time writing this whilst having to block out the swear words, hoping that if the Telkom service ears will not hear me out maybe their eyes will.