Non stop calling after ********* business practice

In May 2016 I paid a substantial amount to cancel my Vodacom contract. Now I have Vodacom calling me incessantly every day with an automated message that I owe them money. When I call for an explanation I get told that my contract wasn't actually cancelled, but a ghost number was assigned to my account that has stayed opened and i get billed on without my knowledge. How incredibly ********* can you get? What does CANCEL mean I wonder? This is unacceptable and I told Zuko when I phoned on 21.08.2017 that I would not be sorting this out and that he should sort it out with the relevant departments as the proof can be seen on your side and it is not my problem, which he hasn't done because I am still receiving your ridiculous calls. Bad service. I will not be paying any more monies over to Vodacom for this contract, and if you do not sort it out ASAP and continue to call and try to blacklist me as threatened I will contact the CPA. Get back to me when you have all your facts and when it is sorted.