It continues to boggle me how Qantas just doesn't know how to act sorry. I thought that kind of "we're never wrong" attitude was the monopoly of American companies.
Just to play the "to be fair" card for shiggles, a doctor's appointment is a lot like a flight. You're offered a time, but there's no guarantee you'll be seen on time.
Of course, it's not very likely a doctor will book you in for an appointment they will knowingly cancel, and at least you don't (usually) pay for a doctor's services until it has been completed.