Vodacom ****** - I want my money after three clearly useless telephonic requests to cancel unused SIM

For months I've been trying to understand and cancel an additional 20g data sim which was miraculously taken out on the same day as another 20g sim. I'm using one and not the other, for a full year now. Three calls later, they are both still active, and the consultant i just spent a whole 21 minutes on the phone now because he talk too much to listen, has the nerve to borderline threaten that he can request a plain cancellation, but if they have to go back to listen to the calls from a year ago, then i will be liable to continue with the contract if i agreed, steering me away from that option. So when Vodacom could be wrong, this is the tactic to deter people from possibly asking for a refund for your wrongdoing? Let's cancel and forget this ever happened! It's not like i haven't been paying for a ****le I'm not using for a whole year, so what's another year of the same *******? You are ****** of the highest order, THE NERVE!! NX