I would never try to deal with telstra (or any other business) on the telephone if I have a problem.  I write a letter, and then they are forced to act on it, and you have a copy if you have to follow up.

I recently had a fee problem with telstra, and could not sort it out by talking to someone in the Philipines, so I wrote a letter, and was contacted by an Australian person, and the fee was waived.  Possibly because I was determined and persisted.