No service from Telkom.

I have been trying for more than a year to let Telkom know, they picked up the devices i ordered and cancellation was discussed within 7 days after order as the agreement says. They still try to deduct instalments from my account twice every month and i have not been able to use my bank account. They have already taken more than R2000 out of my account, and bank fees keep piling up because there are no funds. I have emailed to their customer service and even my local branch in Paarl Mall, but i have received no help. I have phoned, and i keep being transferred from one department to the next... No one seems to know how to cancel this. I have even paid for my bank to cancel the debit order, but Telkom just keeps putting it through under different reference numbers. Have you got any suggestion as to how i can get this sorted successfully?