CANCEL MY VODACOM IMMEDIATELY

I will never recommend anyone to take contract with vodacom as they are not honest with their contract terms, my contract with them ended and I called for cancelation, the agent that assisted me then convinced me to keep the Sim card and still get airtime on a month to month which I can cancel at anytime, to my surprise I called in to cancel and obvious offer the calendar months notice I was told am signed into another 36months which I never agreed to, I asked for a recording as they are mandated to keep records and I have rights to those records upto date they failing to give those records and still billing me, why are they still billing if no prove of contract, this is now considered *****.