i want to cancel my adsl data

I have been trying to get hold of telkom for the past 2 months, i tried calling (on hold for over 30 min at a time). Sms, email ect... Up until today i have received no response. I even tried not paying them, but that to does not get any response. I want to cancel my adsl data as I am paying everymonth for horrible internet coverage. I sit next to the moderm and nothing works. Please could someone call me ASAP