Unstable and extremely slow internet speed

This has started about 3 years ago, We started on a 4MB/s ADSL Line, We then noticed that the internet connection was very unstable, hence we dropped our line speed to a 1MB/s Line, it was running at the full 1MB/s speed for over a year, Then we started noticing that we dont even get 50Kb/s download speed, we have made contact with telkom over 20 times in the last 2 years to get this sorted, but everytime they dispatch a technician to our home, they tell us that the Exchange is to far away from our home??? How is this possible? We have not moved neither has the Exchange but yet we do not get a proper solution to the problem.<br> <br> Please Telkom, Up your game and sort us out!!!<br> <br> Thanks<br>