Since upgrades were done, my internet is unusable

My adsl connection was functioning perfectly well until Telkom decided to upgrade the line without notification last week. Now the connection drops permanently and when it is connected it is unusable. We have logged this fault telephonically as well as via sms and Telkom has notified us saying the problem has been solved where it clearly has not. The line is used daily for business purposes and at this stage it is disrupting productivity.