MTN is cancelation ****ing us

When service is so bad, you can't even cancel it. I have been trying for over a month now to cancel a contract with these ****ers. Every time I phone the customer care line 135, and follow the prompt to get to cancelations. The call gets either cut off or placed on hold and never gets picked up. So then I tried to email a cancelation to their customer care email as suggested on their website. My first email being on the 4th of the month. Thy only rep**** to that 2 days later request some details, which I sent that same day. The next response was 13 days later from their retention department asking for my details again. 10 days later I finally get through to a "champion" in their customer care line. This time I had to go via the other portals, because the cancelation portal still just cuts the line. And then I end up being transfered to 5 different people and having to explain myself to each one. The last one finally put me on hold and just never bothered to come back after I was on the line for about 30min I had to just give up again. Now this morning I go in to a mtn branch and get told that my contract is still not canceled and that the only way to do it is to phone that circus of a customer care line again and cancel it there. This is ridiculous! How do I cancel with these clowns? Please help! And thy just keep taking money!!!!