Poor service delivery

About 4 months ago Telkom had a special on their ADSL line. One could get a 10 mb line for R599 per month. For the first 6 months you only had to pay R249 per month. I subscribed for the special. Since then I have been charged for a 10 mb line and a 4 mb line. It is impossible to have two services on one line. Spoke to telkom customer services 4 times. Some of the charges were reversed when I called the first time but I was stil being charged for 2 services. When I called accounts the the 3 rd time they said that they will refere this to sales but nothing happened. The forth time when I called them I was advised to call sales. I called sales twice and both times they promised to fix the problem but until today nothing was done at all. It is pathetic to say the least. My account keeps ading up. They do not have the decency to call me back.