ADSL line very slow

Our company busines ADSL line is ***.<br> Between the hours of 18h00 through to 07h00 we have a high speed 1MB line.<br> However, durning office working hours our speed drops down to 15 - 20KB.<br> 70% of our company software is web based and we are unable to access our software without being timed out. We are unable to do internet banking durning working hours.<br> This problem has been reported a number of times in the last 12 months, the issue gets sorted out at the local exchange and then 2 weeks later we are back to a slow line again.<br> We need the line upgraded and sorted out ASAP please<br> We are happy to pay more for a faster line that will maintain its speed durning working hours<br> The situation has become urgent and we would appreciate a response.<br> We attempted to contact Telkom via telephone over the last 2 days, however even at 08h00 in the morning we could not reach a consultant after holding on for more than 30 minutes.