Vodacom makes it impossible to cancel expired contracts

My Vodacom Data Contract expired after which I received a phone call from client services to upgrade. New contract was for 20G @ R149 per month. After 2 months still no change from old contract. Another 4 months passed and amount deducted went up to R464.95 and still no extra gigs as per original discussion. I never authorize this new month-on-month arrangement, in fact cancelled the whole thing but debit order still went off on monthly basis. Many reference numbers of my phone calls available eg ***; & ***. Had to force stop debit order at bank. It is not possible to cancel expired contracts with Vodacom and they would rather prefer to black list you instead when you have no other choice to force stop debit orders