I sent a book which is scheduled to be labeled lost in less than a week.  I did not use DC.  I have PM'ed the requestor to remind them to mark it received if it was, but have gotten no response.  Am I correct in assuming I'm just out the book and will not get the credit?  (I have no real problem with that if that's the rule, but I can't really find what happens if a book is not marked received and the requestor never responds to PMs.)

As far as I know, yes. I use PBS postage so I can mail from home but the DC os so worth IMO. I recently had a similar situation where weeks after being scaned received the receiver still hasn't marked it or responded to pms from either me or PBS. PBS said he hasn't even logged in in weeks. I got my credit when it was marked lost because I used PBS postage. If you don't use DC and somewhere along the line they remember to mark it even after it is declared lost you will get your credit then. 

Either way PBS will be in contact with you and the receiver before it goes lost and will do their best to try and get it resolved. They don't like undelivered books either. 

Also, I have heard of cases where the site administrators will give credits for outstanding transactions from a member's account, if they determine the member is inactive, and they close the account, and there were credits available in the account when the account is closed.  So, there is a chance you may see a credit for this if the member is inactive and account is closed by TPTB.

You cannot assume that the book will be marked lost in a week. What actually happens is that when it's time to take action, just before the date shown on your account page, the system will first do some analysis.

If the other member's account appears to be abandoned, because he has not logged in for a while and has not responded to the "please login" emails that the system automatically sent him, then the book will be marked received and you will get the credit.

If the other member has been logging in and has just not marked the book received, then the system will assume he did not get it and will mark it lost in the mail. If the book is marked lost, then you will not get the credit unless the member later goes to his transaction archive and marks it received.

Yes, if the book ends up lost you will not receive a credit for it (unless you purchased one of the credit assurance options).

If the book arrives (at any point) and is marked, you will receive the credit (even after it's moved into the lost catagory).

What Sara said -- if you send a note asking if the book has arrived (near or after the lost date) and don't hear back within a week, go down to the bottom right corner of any page here.  Under "company" click on "contact us" and use the Feedback option there.  Tell them you PMd, asked for a response, and haven't heard back.

Thanks to everyone for the replies.  (I wouldn't contact PBBS until after the "take no action until" date anyway.)

For all those who have a PayPal account, you can print postage from that account that includes DC.  I never go to the post office.  I print all my postage through my PayPal account with DC (an additional .19 for Media Mail and often free for First Class).  If I am shipping a lot of books, like I did recently when I posted quilting books, I even have the mailman (actually, mine is a mailwoman) come to the door to pick up the books.  I love the Post Office employees!

Another factoid that many people don't know is that it's cheaper to mail a paperback book First Class as long as it weighs less than 10 ounces (which most PB's do).  

Kate, Keep in mind that buying DC from Paypal will not guanantee your credit from PBS.  Using PBS DC will get your credit as soon as the book is scanned into the USPS system and if the book is never marked received, you will keep your credit.