Wow!
I feel your pain. If it was mine, I would examine the internals and replace any part that looked "altered". That would probaly include the hammer. Which you can find on ebay for around $50.00
At the very least, I would contact the seller and voice my dissapointment/issues. If you cannot get any relief from the seller, (partial refund/return the gun) then I would work at trying to make a fully functioning revolver out of it.
That would be my advice... FWIW
At this point it seems to be a $400.00+ paperweight.