I have a book I requested on 2/26 that the person marked mailed on 3/8.  I got a PM that said she had gotten a lot of requests, and the book should be mailed soon, as soon she is financially able to mail it.

 I can't even cancel the order, because it's already been marked mailed.  Is there anything I can do to cancel this transaction?  Can I just say don't bother mailing it?  Then it would just time out on the action date?  

If you marked the book mailed but did not mail it and you want to mail it late (more than 4 days after the date you marked it as mailed),  you MUST contact the requestor using the PM button on the transaction, to be sure that the requestor still wants the book.  (If the book has already been declared "lost", the PM button is on the "lost in mail" transaction in yourTransaction Archive.)

• If she replies that she does still want it you can mail it to her.  She can mark it received and you will get credit at that time.
  • If the book has already been declared "lost" she can mark it received from her Transaction Archive and you will get credit at that time.
• If she replies that she does NOT want it (she may have gotten a copy from someone else in the meantime), you should NOT MAIL - you should ask us to cancel the "en route" transaction and you can repost the book for someone else to request.
• If she does not respond to your PM, you should repost the book.  It will be offered to her automatically if she still wants a copy.
• You should not mail a "lost" book to the original requestor unless she has confirmed that she still wants it in a Personal Message.  If you mail it and she has already gotten another copy, she will NOT be obligated to mark the book received, or to return it to you.

It seems I found my answer!  If they have already marked it mailed and it is beyond 4 days since the mail date, they have to ask you if you still want the book before mailing.

If you want to request it from someone else, she needs to have PBS cancel the request so you can reorder it.  But at this point, it might be quicker to just wait for her, depending on how much longer she thinks she needs to wait.

And as for the question in your subject line, the other recourse is that she WILL be noticed by TPTB for this behavior, as long as you remember to fill out the survey when you get the book in the mail finally.  Make sure the postbark date is filled out, they compare it to the required shipping dates and mailing dates.

Let things stay the way they are; if the book arrives after being declared lost you can still mark it received . (or not) It will be up to you. Perhaps you would feel better if you sent the member a PM letting them know you are disappointed.

I always fill out the survey and note in the comments box that the postmark was clear in indicating the mailing date so there's no question.  PBS will track late mailers and that can endanger your PBS account.

Book requests are not open ended.  I agree with Rhonda, if the sender cannot provide a mutually agreeable mailing date she should have the transaction cancelled and repost the book FIFO later.

From the PBS help docs:

If you marked the book mailed but did not mail it and you want to mail it late (more than 4 days after the date you marked it as mailed),  you MUST contact the requestor using the PM button on the transaction, to be sure that the requestor still wants the book.  (If the book has already been declared "lost", the PM button is on the "lost in mail" transaction in your Transaction Archive.)

• If she replies that she does still want it you can mail it to her.  She can mark it received and you will get credit at that time.
  • If the book has already been declared "lost" she can mark it received from her Transaction Archive and you will get credit at that time.
• If she replies that she does NOT want it (she may have gotten a copy from someone else in the meantime), you should NOT MAIL - you should ask us to cancel the "en route" transaction and you can repost the book for someone else to request.
• If she does not respond to your PM, you should repost the book.  It will be offered to her automatically if she still wants a copy.
• You should not mail a "lost" book to the original requestor unless she has confirmed that she still wants it in a Personal Message.  If you mail it and she has already gotten another copy, she will NOT be obligated to mark the book received, or to return it to you

If she wants to mail books late then she should only post books on Bookmooch where people wait months to send books, one of the reasons I have become disenchanted with BM.   

I have 2 books I am waiting on.  One is coming from PA which is the next state up from me.  It was mailed on 2/21 ok

the second was mailed on 2/14  and is coming from one state down from me LOL.

I mailed a book to Pa. and it was delivered in 2 days. 

So I just wait and pray that the books I am waiting on get here soon

if the book arrives after being declared lost you can still mark it received . (or not) It will be up to you...

That's not quite accurate.  Unless you've already received another copy of the book after this book went lost,  and the postmark indicates it was mailed within one week (or later) of the date it would go lost, you're obligated to mark the book received.

But you could write to her and say something like, "Thanks for letting me know.  If you can't mail the book by (date), please ask the Admin Team to cancel the request so that I can get it from another member."  Tell her to go down to the bottom right corner of any page, and under "company" to click on "contact us" and use the Feedback option to ask them to cancel it.  Be sure she tells them that you want the book, but don't want to wait for her to mail it.  They should cancel it from her end, so that your request is passed to the next sender.

PBS will cancel books that have been marked mailed.  But PBS will only cancel them if the sender asks for it.  You are at their mercy.