Irrational "Technicians"

Firstly thank you telkom for sending me a bill for a problem you did not fix!!!! As you are aware the consumer protection act protects me against companies like you who charge customers for something that you did nothing about! For 2 Years I have had an internet connection running at 4mbps until a few months ago when the line became unstable. A technician came and changed some wires and said that's all he can do. After a week I filed another complaint and a second technician arrived and said I was to far from the exchange and will never be able to have a 4mbps line. How could I have had a 4mbps line for 2 years without any problems or any complaints and now suddenly I'm too "far" from the exchange with frequent line drops? Did you move the exchange or are your technicians just to lazy/*********** to fix my problem?