OK.....that's a pisser and I would be pretty annoyed too

. Have you contacted the seller to ask why the f@#k he didn't see fit to mention any of these issues, (I know the sorta feedback he would be getting from me).
Not having the clear transparency piece for this particular kit can be a show-stopper, as it incorporates part of the upper fuselage crown, as well as the cockpit window panels. This would be very hard to replicate or substitute for with Miliput bog or alike.
Troy, I will go through all my Revell 737-800 kits to see if, by chance, any of them have a spare transparency piece, (this has been known to happen on occasion), in the mean time I would contact the seller, (if you haven't already), and ask him if he still has this vital piece.
TOR