The problem appears to lie with the organization of the company. They all consist of independent groups who don't seem to speak the same language, let alone attempt to speak to each other. In addition, it's almost impossible to achieve any continuity: they must be the only big company I know which doesn't have a postal address.
This page gives an overview of the problems we've had over the years.
November 2000: Line outage due to backhoe damage. This is the only time Telstra has ever honoured the legislated Customer Service Guarantee. It's tempting to think it's because they found somebody else to pay for it, or maybe because they had digging equipment on site.
February 2003: One week line outage. I wrote a lot of detail about this one, since it was so disruptive and indicative of complete inability and incompetence on the part of Telstra.
June 2005: no resolution within the terms of the Customer Service Guarantee.
July 2006: The first time they ever fulfilled the Customer Service Guarantee for a cable fault.