Well first off I know all of those who ordered are upset I don't blame any of you. I wouldn't post on a public forum or even hint at doing anything to Dan it's not wise and there's better ways to do things.

First thing did you pay with Visa or Mastercard and has it been more then 60 days?

If it hasn't been more then 60 days disput the charge with your bank, you didn't get what you paid for (some nothing at all)they will contact paypall to get your money back.
Those of you who did get there parts and they don't fit would need to send the item back with proof and a tracking number to provide to Visa so they can contact Paypall and get your money back.

Don't wait for him to decide if he can refund you likely he can't because the money was invested in the parts (makes sense to me) and I doubt he can afford to pay all of you out of pocket. Visa has insurance for these type of things it happens all the time.
But don't wait to disput it otherwise you may have to go to small claims and it's a big hassel.