Glitch report, I guess, or maybe someone could clarify why it's not working? When I use a mending book on any tool or armour using an anvil, it comes out the same as it was, and doesn't apply the book. I haven't tested it for other books; only mending, though it may still be problematic. Here...

You can charge back but I wouldn't reccommend it as you will get blacklisted and it is basically scamming.