Telkom keeps charging for cancelled services.

I cancelled two small 10Gb contracts 3 months ago shortly after they matured. Naturally Telkom conveniently did not remind me of the impending maturities, but in any case I sent in my cancellation 3 months ago and to date have not received a single case reference number or anything. I followed up again a 2nd and 3rd time and even sent the cancellations from two different e-mail addresses in case there was a mail-delivery issue???? I thin went as far as registering on Telkom portal and logged the cancellations there too. Still no communications from Telkom. I had my bank stop the payment to Telkom as they kept taking money off my account even though I had submitted cancellation with 1 months notice. So what does Telkom do.....they change the debit order to the middle of the month to ***** my money. This has continued and I dont know what to do to get Telkom to act honestly.