https://www.siliconvalley.com/2022/09/19/travel-troubleshooter-can-i-get-a-refund-for-these-airline-credits-on-expedia/

DEAR TRAVEL TROUBLESHOOTER: For eight months, I have been trying to get a refund from Expedia for my unused flight credits. I had canceled my flights back in 2020.

Expedia offered me a partial refund, after I rebooked a new flight for December 2021 that used two-thirds of the original flight credit. But I had to cancel that flight, too, because American Airlines kept dropping flights.