You must take a few steps to cancel or refund a Qantas Airways flight. You must first inform the airline in this regard, and you must also cancel any linked hotel or car arrangements. It would help if you got in touch with your credit card provider to ensure the refund is handled correctly. The only thing passengers need to do is call Qantas customer service at –OTA: ( 1 800 227 4500 or +1-855-738-4459 ).

Can I cancel a Qantas flight and get a refund?
You must follow a few steps to cancel your Qantas Airways Flight. It would help if you first spoke with the airline directly.
You can do this by calling their customer support number or visiting their website. You’ll need to have your reservation number on hand when you contact them.
Moreover, you will need to reschedule any scheduled connecting flights. The airline that runs those flights is where you must do this.
Moreover, you must inform any hotels or rental car companies that you have arranged to cancel your bookings.
Finally, you need to contact the company that issued your credit card and inform them about the canceled flights.
They might provide you with some defense against the charges.