Vodacom contract cancellation is worst

My Vodacom contract is ending on the 17 of November 2019.called Vodacom that I want to cancel my contract I dnt need a new device or airtime.i have called more that 5 times.and every time I call I talk to a different consultant.who promise to cancel and until today no one had helped.the system says my contact is ending 2021.when I ask how there's no answer to that.my contract started 2017 November 17.