Pathetic service to loyal Vodacom customer when trying to cancel a contract.

I went into the Vodacom store to cancel my phone contract ( Blue Route Branch) I was put on the phone with the cancellation department and they confirm I would pay my last debt order on the 30th of October. I then phoned a week later to confirm the amount and the sales women said that it will be on the 30th of October. its the 16th November and I received and invoice for a sim only contract. what was the point of me cancelling the contract when you are going to keep billing me for sim only contracts when I specifically said I want to cancel it. Terrible service from Vodacom. i have not missed a single payment but when I want to cancel my contract I run into every issue to try and stop me from cancelling