This was only for a small amount (£2.99) and I’m glad that it wasn’t for a larger transaction, however, I bought a Kindle book for £2.99 on the 9th December and it seems to have changed my underlying card twice.
I’ve sent a message using the app and Curve said it would refund in 2 days, but nothing seen as yet. I replied to this message but no response.
To make things more complicated, before I was concerned about the double charge as I thought it would be refunded soon, I went “back in time” to change the transaction to a different card. The new card was charged, and the original card refunded, but the other 2nd charge is still there.