I currently have a issue with Telstra regarding speed especially during typical congested times. My issue has now gone through 2 months worth of TIO processes as Telstra have admitted the exchange I am in is congested and have no plans to make any improvements.
What was interesting though is the speed changes occurred as I received a notification from NBN that work is scheduled to start in Feb 2014, which suggests that the infrastructure may have been raided to prop up another area.
So far it is not likely TIO can force a change to increase the speed but this maybe an issue limiting speed. Do all the other checks first including
www.speedtest.net as there is a representation for different providers.