Notified an A to Z claim was not found in my favor– buyer never reached out, and I was never made aware a claim had been opened (today?)

I sold a book on August 29th.
I was supposed to arrive on. Sep 20th.
I noticed three days ago that there hadn’t been an update after a certain point. I shipped out a second copy. It should arrive by Monday.
I got an email in my inbox today “Claim decision on order X”
The claim was opened today and appears to have been granted today. I did not never got a notification a claim was opened today! Just the notification that the claim was decided. The customer had not reached out to me, either.
I’m happy to refund and eat the cost of the book, but I want to appeal the A to Z claim mark. If A to Z claims now can be automatically approved when a book is lost in shipment & a seller doesn’t catch it/the buyer doesn’t reach out, that’s bad news for sellers.
How should I write this appeal?