My not PBS DC states 4 books where delivered and receipient won't mark them received or answer PM's    Do I still have to wait till the date PBS say's not to contact them until?

Also being bombarded again with damaged books and though I marked them as such upon receipt the senders (yes multiply) are ignoring the PM's.  Is there anything else that can be done to get them to make good.  I am growing very weary of losing credits and having no books to repost for the loss.  I am ready to put a condition stating do not send me damaged books but that seems a bit redundant.   Ignoring the pm's is as good as admitting they know they've done wrong.    Is there some way the powers that be could use that for a reason to refund our credit?

For the first issue, here are the instructions from the Help Center:

If you sent the book with DC purchased elsewhere and it has been recorded as delivered by USPS but hasn't been marked received yet:

• First, contact the requestor from the active transaction (in the Books I've Mailed tab in My Account), or from the "lost" transaction in your Transaction Archive if the book has been declared Lost in the Mail by PBS.
• If the requestor does not respond to your PM within five days, contact us and we will look into it.
• We cannot grant credit for DC purchased outside PBS, but we can check if this requestor has become inactive.
• If this requestor is inactive, your book should be marked received by the system.

For the second issue:

Once you have marked the book(s) received, give the sender 5 days to respond.

If you don't hear from the sender within 5 days:

• For problem books that were marked received and are now in your Transaction Archive: go to your Transaction Archive  and click .  Then choose "The Sender has not responded."  This will send an email to the sender, making it clear that she or he needs to respond or forfeit credit for this swap.

If you don't hear from the sender within 2 days after you have done the above to send that "follow-up" email to the sender, contact us.  Failure to respond (in an active account) is considered admission of fault in a problem swap.

If the sender responds and resolves the problem:

• You should mark the problem 'resolved' from the Transaction Archive, as described in Follow-up on Problem swaps.
• 'Resolved' does not require a credit refund - you can mark 'resolved' if you consider that the sender has done what was needed (even if that was nothing).

If you made an error and the swap was not actually a problem:

• You should remove the problem status from the swap in the Transaction Archive, as described in Follow-up on Problem swaps.

If the sender responds and disputes your description of the book:

• We understand that two people can look at the same book and describe it differently with regard to its condition. If you believe the book was unpostable when it was mailed and the sender disputes this, you can offer to share digital images of the book with him or her.
• You can do this by uploading the images to a free photo-hosting site (such as photobucket) and send the other member a link to the photos on that site. You can also send the images by email, if you are both comfortable sharing emails with each other.

• If the problem is NOT resolved by the sender (and negotiations between you are finished),

  • choose "Problem was not resolved"  in your Transaction Archive, as described in Follow-up on Problem swaps. 
  • It is best to wait a week before marking a problem swap "unresolved"- this can't be undone.

Thanks Bunches Cathy I didn't see that.

Also note, from the Help Center document on problem swaps (Highlighted areas are my emphasis.):

You do need to reply to the requestor if you get a report of a problem swap, and resolve the problem if there was one.  Because the requestor can provide follow-up on how the problem was handled, resolving the problem will greatly reduce the effect of a problem swap on your account record. Unresolved problems (or not Responding to PMs about a problem swap) will more seriously affect your account record, if a pattern of this accumulates on your account.  Remember that one problem swap will not harm your account, even if it is marked as unresolved by the requestor who gives follow-up on how you handled the problem.

If you don't respond to the requestor about the problem within a week, we may step in - although we cannot assess the truth of a situation, if one member is refusing to communicate with the other, that member may be judged as "in the wrong" for this reason and non-response will be taken as admission of fault on the part of the sender. Courtesy is important!  We know a problem swap can be frustrating, but it is important for both members to remain courteous during the process of discussing/resolving the problem.