I have the same question as this thread-

I used a 15% off code to book tickets in mid January. I cancelled the ticket within 24hrs due to rumbling over corona (trip to was Japan in February 2020).

I was charged but got the full refund- however when I try now to use this AC code on the website for new itineraries, it is telling me that it has been used already.

Do I have a case to request this code by re-activated, esp as cancellation was within 24hrs- so all elements of the ticket should be refunded??