I hope that I'm not rubbing salt in a wound, but my experience with wrecking yards is that almost always they try to say that an engine is one year newer than it really is. I can't tell you how many I have sent back without allowing them to be removed from the delivery truck.
They really should be willing to be of more help here.
It sounds like you have offers to help with getting the correct heads. Why not take them up on it and be done with it.
In the mean time, file a complaint with whoever might be able with getting a partial refund. The better business bureau, the state department of consumer affairs, etc. Don't expect a refund and be pleasently surprised if one comes through.
Life's too short to spend too much time trying to force them to make it right.
