I think I stumbled across similar behaviour, but for a used book. I was looking for a particular computer science book, couldn't find it new, and then decided to buy a used one from Amazon, ordering from the store with the best rating. It didn't arrive, and after a while (a few weeks) I received a notice that the delivery service had lost the book. I was refunded the money, though. The tracking number I got for the book from the store never worked though, I checked multiple times during those weeks. So I guess the same thing was at play here: I was sold the book although the store didn't have it. After failing to acquire the book, they just cancelled my order by pretending the delivery failed.

This boring story has a happy ending: I contacted the author (a retired MIT professor) if he could share a PDF with me, and he generated one from his old roff sources. He also sent me a signed copy from a stack he got from his publisher back then (80's), paying over $60 porto (US -> UK). I was blown away by his kindness and generosity.