vodacom doesnt want to cancel contract

my contract expired end of July, called beginning of July to put in my cancellation notice, Itumeleng didnt do his job because im still being billed for the contract i no longer want. called again last month, was promised it would be cancelled but come the 1st, airtime was loaded again. made another call on Sept 1st, Vineshree(i think) told me my query has been escalated and my contract cannot be cancelled because i have to be credited, that sounded like more nonsense to me. she also said someone from their escalations will call me, no call received from vodacom. cancel my contract and move me back to prepaid, i no longer want anything to do with vodacom or their products that they keep offering whenever you want to cancel.