TELKOM MISCOMMUNICATIONS

I have a small mobile router, on contract ,from Telkom. Debit order. I HAVE TRIED FOR 2 YEARS TO CANCEL. I tried customer care. Mechanized options, nothing about cancellations. Eventually I got a live person, she said I owed them money. Yes, because I was trying to cancel the product. I paid, over R1000 to settle the account. Was it cancelled? NO Sure as nuts, there goes the debit order off again, month after month. No one to speak to. HOW CAN I CANCEL?