Why Telkom, Why

The exchange in our area i'm sure is not running more than 20 Data lines. I have logged numerous calls with Telkom, all with the same problem. Line speed. Im paying for a 4Mbps line, but i'm only receiving sometimes 1Mbps at night less than 1Mbps. Why should I keep paying for this, this has been going on since January this year. Telkom send a tech, (or Call centre just resets my ports, cause that's all the useless people can do), my line is then fixed for about an hour than it drops again. When will this problem be taken seriously and they send someone to check what the Hell is going on with this exchange. every time a tech fixes the line, he says he can see there is a problem in the exchange, and he will escalate it. but nothing ever happens, I know that I am not the only one with this problems, as other people in my area aren't even paying there telkom line anymore. I work with remote support and cannot afford to have a slow/Non existent line. Can this please be taken up as a serious problem before you ****heads receive another bonus, and sit back and do nothing again!!!!!! Bragging about new products and idea's, when you cant even supply S.A with a Quality DSL service.