ADSL Line speed

I have a 2048kbs line. On the 23rd of December the line sync speed suddenly dropped to 1275kbps. I logged a fault and it was said to be resolved but it was not. When contacting the Telkom representative they said that is a fair speed and they doubt it will be fixed. This is not acceptable as my line has never had speed problems like this, it is almost half the speed it should be. Please can you resolve this ASAP as I do not see the point in paying full price for half the service/speed it should be. My reference is 1104CRK050116