Qantas complaint: Failure to pay refund

In June last year, I tried to redeem a travel credit for $1000 that had been issued to my frequent flyer account. When I was unable to redeem the travel credit online, I rang the call centre who informed me that it had expired and it would instead be issued as a refund to my credit card.
Over the past seven months, I have spent more than 20 hours on the phone to your call centre, spoken to over 14 different customer care representatives and opened two customer care feedback forms. Over this time, no member of the Qantas team has ever contacted me regarding the status of my claim.
As it has now been so long since this refund has been processing, the original credit card I used to make the booking has expired.
Your team has now told me that I need to obtain a Statutory Declaration from my bank to verify the credit card details in order for them to process it. In short, I am being asked to spend more of my time to resolve an issue of your making. This is after 4 successive calls in which I was told that the refund had already been processed. I have asked to be issued with a travel credit instead of a direct refund to bypass the need for a Statutory Declaration, and have been told “this is not possible”.
This situation is absolutely appalling. I am a regular customer of your airline and I have never, never received such a poor customer service in my life.