Welcome to AFF,
ellvie.
I am sorry to hear that you are disappointed with your experience described. I have experienced a similar delay when travelling to SYD and a mechanical problem caused us to miss the Sydney curfew resulting in an overnight delay to my journey. However, mine was from BNE to SYD on a paid ticket and flights operated by Qantas. But does show that the delay can happen any time we travel and often unavoidable.
The main issue with your experience as described is that you were not offered overnight accommodation for the delay, which I would expect the airline to cover in these circumstances.
You would have been aware at the time of bookin your award flight that it was to be operated by Jetstar. That is shown on the award booking page, and as a Gold FF member you would likely have known flight numbers in the 5400 range are not operated by Qantas.
I think is quite reasonable for the airline (be it Jetstar or Qantas) to refuse a voluntary change to the booked flights even of the previous flight has availability. These are standard conditions of award tickets and I would expect the check-in agent to refuse a change without there being award seat availability and charging the published award ticket change fees.
The fact that the booked flight was then delayed and cancelled is unrelated to the previous flight not being fully loaded. It is unfortunate, but unrelated.
If your flight is cancelled due to something such as a mechanical failure or crewing issue and you are required to remain at the point of origin overnight, I would expect the airline to accommodate you. If the cancellation is due to weather or other situation beyond the airline's control, then you are responsible for your own accommodation as per normal.
Rebooking the displaced passengers for the following day will be based on some priority criteria as determined by the airline. Sometimes they will do this based on FF status and sometimes based on fare paid. It appears the latter was used in your situation resulting in being placed on the later flight the following morning. This is again unfortunate, but a risk we take when using FF award tickets.
ellvie said:
I believe the used by the Qantas FF Program for such a flight is
Award, not Reward.
By all means complain to Qantas Customer Service. However, I believe the only valid grounds for complain is the lack of accommodation provided for the overnight delay, assuming the cancellation was caused by a mechanical or crewing problem rather than weather related. If you have the accommodation receipt, then try writing to Qantas Customer Service and sending a copy of the receipt and requesting they refund you for your additional expenses.