Someone requested a book I'd posted but used another title than the one that comes up with the ISBN.  I sent a request back clarifying the title and he replied back that it seemed to be the same title, and that he wanted the book no matter what because he loved the author.  I sent the book immediately, he received it immediately, and then complained that it was a repackaging of two books (which was why I'd sent the PM to being with) and that the edges had been chewed.  There was the most minute fraying of one edge - less than 1/8 inch - certainly not chewing - and wanted a credit back.  I believe he wanted the credit because of the repackaging of the 2 books - an issued which I had clarified with him before sending the book (which he has acknowledged was his fault, not mine) - I know enough not to do business with him anymore - but is there someone to alert others to the fact that this person doesn't operate in good faith? 

I guess I don't understand...what part of this is where he is not operating in good faith?  It doesn't sound like the requestor did anything wrong.  He gave you your credit am I right?  He has every right to request his credit be returned but, that does not mean you have to return it but, that is also not defined as "not operating in good faith."

But, to answer your question you can always report it to TPTB using the Contact Us link at the bottom of the page.

I don't think there's anything you can do, unfortunately, besides reporting him if you feel it's warranted. If enough people have problems with him, the PBS team will most likely look into it.

You had the book posted correctly? Verifying that Title, author, ISBN and Binding Type all matched what the PBS system says?  Then you did nothing wrong on that aspect.  If any of those 4 items differed on the book you had to what the system listed then you had the book posted incorrectly and I would probably return the credit. If you had it posted correctly and he just didn't know what he ordered, thats his tough luck.

If he continues to badger you, or gets abusive, you can use the Contact Us link to report it to the site admin.

Are you saying you posted the book by ISBN and that ISBN brought up another book title?  Or did he order teh book and then ask if was really another title by the same author.  If the title did not match when you posted the book it should not have been posted or sent out. I wouldn't have sent it even with his agreement that it was ok to send.  Publisher's sometimes reuse ISBN and rename books and if it all that stuff doesn't match then it's best to post the book without the ISBN. 

Not sure what to say about the fraying pages. Pages aren't supposed to have any tears at all but then is this really a tear?  Hard to say without seeing a picture.

he replied...he wanted the book no matter what because he loved the author

Don't give him his credit back.