Poor Service - Ripping people off

For months, myself and other people in my area are experiencing slow speeds. Sometimes, we get speeds of less than .5mbps even though we have 4mbps lines. Telkom technicians have told us that there are congestion at the exchange and we were due for an upgrade last year, but this never happened. Even though the exchange is congested, Telkom is still milking this *** for all that it has left. Every week new lines are being installed and the ADSL service is getting worse and worse. To me, this is ripping people off. We pay for 4mbps lines and we expect to get decent speeds for the amount of money we spend. When can we see this fixed? And, please stop adding new lines to the area, until the problem is fixed!!!