One of my wishlisted books became available a few days ago. My account is set so that PBS notifies me when books are available, but it does not automatically request them (this gives me a chance to modify my RCs to suit the type of book I'm requesting). When I requested my wishlist book, I also requested another book off the sender's bookshelf to allow her to save a bit on postage. The sender PM'd me with a question about whether or not I really wanted the second book. I told her I did.

Both books are still showing on my "Books I've Requested" page, but the sender PM'ed me today asking that I re-order the second book as it is not showing up as a request in her PBS account. I'm pretty confused as to how this could have happened; two credits have been taken out of my account, so I'd imagine that both books have, in fact, been requested correctly.

Anyone have ideas on this situation?

You might have requested it from the book detail page, rather than from her bookshelf.  Go to the "books I requested" page an press on the PM button.  Is it the same person as the other book?  If not, then your order went FIFO rather than from her shelf. 

This is a common mistake.  I've learned to always check that I'm on the bookshelf page.

You can cancel the second book up until the time they print the wrapper.

ETA   FIFO  = First In, First Out.

Emily is correct. This happens alot. :0)

Did you PM her to tell her you were ordering the second book? If so, then I'd say it's what Emily said.

If she PMed you independently after you ordered the second book, and you check like Emily said to make sure it's the same sender, you can always tell her to contact PBS about it because it could be a glitch on her end.

Ahh...Ive been trying to figure out how to check to see if both books were coming from the same person. The advice to click the PM button worked, but it's led me to another question. I know I ordered from the same person's bookshelf; she PM'd me about the second book, so I don't know how she could have known about it unless unless I'd ordered it the way I'd intended. However, the second book is, indeed, coming from someone else. Out of curiosity, I went back to the first sender's bookshelf, and when I tried to click on the "request" button for the first book, I was told that I could not request it because my first request was declined.

If I'd requested the book off of a member's shelf, and that member declined, does the request automatically go into the FIFO queue?

If they decline the request, then it does go FIFO.

Maybe the first member accidentally cancelled the request for a second book when she pm'd you?  Or forgot to accept the request and it timed-out?

She may have declined your RCS and that would pass it on to the next person.  Don't know what your RCS are but it's possible that she had one book that met them and the other one didn't.