Did you ask them to respond? 

When I mark RWAP if I don't ask for a credit return, I consider the matter closed and mark it resolved immediately. 

Depends on how your message was worded.  If you didn't specifically ask for a reply, many people just make a mental note to check closer (or whatever) and don't reply.  Guidelines also suggest waiting something like 5 or 7 days for a reply. 

Like yourself, sometimes all I'm looking for is a courtious response to consider the matter resolved. An 'oopsie' acknowledgment, or agreement to read swappability guidelines again.  But the sender doesn't necessarily know that's what I'm looking for.

You can try another pm, 'wondered if you received the previous message and understood the problem before marking the transaction resolved...' 

Robin, sorry to hear about your negative experience.  You are correct that there are ways to follow up when the other member fails to respond.  The guidelines on what option to use and when to use them are listed in the Help Center under "Follow-up on Problem swaps"

Personally, when I have this type of RWAP (where I'm not asking for a credt refund), I include a statement like this: "I'm sure it was just an oversight on your part, and I'm not requesting my credit be refunded, so as soon as you acknowledge my message, I'll mark it as "Resolved"."  It has worked well for me, so far.

Mind you, for a book like the one you described, which was clearly damaged and could not be reposted, I'd have asked for my credit back, but that's a whole 'nother discussion thread. 

Thanks, Elizabeth, for the help with wording.  I'll save it for future use.  :) 

what is rwap, and how can i find out about it.

RWAP = "Received With A Problem"

When you mark books received, they are either received in good condition, or received with some type of problem.

Here is all about it:

http://www.paperbackswap.com/help/help_item.php?id=652 and here:

http://www.paperbackswap.com/help/help_item.php?id=655