Still waiting for answer from the PBS folks, but don't want this to time out (which it will do in about 12 hours)-- a WL book got offered to me, I accepted, but it got cancelled due to my requestor conditions. So the next day I sign in, and acct says I have 2 WL offers.  Surprise--- 2 offers for the same paperback book, but with 2 diff ISBNs. (when I originally put book on my WL the other ISBN popped up as an alternate so I added it too)

Now I don't know if I should accept one and decline the other or what..........

it is really a decision you have to make, do you want one ISBN over the other or are you willing to chance getting both and reposting.  you had both on your wishlist...that is a risk you took.

If you have enough credits, I would accept both of them. You never know if it will get canceled again with your RC. If you get both books, you can always repost one.

Accept the one that will expire first as soon as possible. Let the second offer timeout unless the first person declines your request before the second one has expired, in which case you should accept it.

If the first member declines your request after the second offer has expired, write to PBS and explain what happened and ask if they would consider giving you back your place in line for ISBN xxxx. Other people have occasionally posted stories about getting their place back after very unusual things like this happened.