Catpawski - I, too received quite a few non-I Spy type squares. One was completely solid brown. I wonder if someone had them packaged up for another swap and accidentally sent us the wrong ones? Too weird! Surely it was a mistake and hopefully won't happen again. Anyway, I figure I can cut them up and use them as 2 1/2" candy squares, so not all is lost.
As for returning blocks to the original sender if they don't meet the expectations of the swap, I don't think that is out of line. Perhaps she really did send in the wrong package and would like to correct the mistake.