I have 4 books that different people ordered from me.  For various reasons (two had underlining as they are textbooks and the other two books indicated to be sent to the same exact address but were ordered by different PBSers, so I wanted to know if I could send them together) , I had to PM them prior to sending them to see if I could still send them out. I did not hear from any of them, and time ran out (for marking the book as having been mailed) so I had to cancel them.

I reposted them, and lo and behold ALL 4 of them immediately were taken by the SAME four people with a wish list hold on them. So frustrating...they need to be made available to other PBSers...these PBSers have not responded to my PMs in the past 5 days so they must not be near a computer these days. I wish they would just go to the next person in line instead of having to go through all this again with the exact same people who aren't answering my PMs!

I would go ahead and mail them - textbooks can be posted with underlining.  If you're not sure about the two going to the same address, send them separately - then you'll get your credits.  It may be that they haven't noticed they have a post - with the new system, I missed one for two days!

I can understand why you didn't mail the two books with underlining, but why didn't you mail the other two?

I wouldn't mail the one with underlining without the OK from the requestor, because the markings have to be agreed to in order to get your credit. I'd go ahead and mail the others, though. If they are not the only wishers and are not responding to your PM's, I'd ask R&R for some assistance.