Telkom ADSL very slow

I have a SmartHome Advanced package with 4MB ADSL and internet service with Telkom. The ADSL line generally runs at 4Mbps download speed however since October the line has been running very slow at 200 - 500 Kbps in the evenings and over weekends.<br> <br> I have reported this problem on six occasions over the last two months on the following reference numbers 422CRK121215, 875526, 875525, 875459, 875163, 828851.<br> <br> Usually I just get an email response from Telkom that the fault has been repaired by recreating my ADSL port. <br> <br> The original problem however persists as the line is now permanently slow.