Still paying for a service I have never received

I signed up for Wireless internet at my house in Midstream last year in March. Apart from the day of installation there was never signal strength enough to actually do anything on the internet. I cancelled and returned the router to Telkom's office in Centurion mall however they are still debiting my account more than 9 months later despite numerous calls and e mails and even up to so called \executive escalations\"<br> Now this month the debit has even increased by R459!<br> All I can say is NEVER SIGN A DEBIT ORDER WITH TELKOM!"