It sounds like you did everything BUT the one thing that you should have - taken the bike back to REI. You say you "took a stab in the dark and tried ordering a couple of them that were similar" and then "spent a good portion of my day trying to find out from REI who the bicycles manufacturer is", but for some reason you didn't just take the bike in and ask them to replace the hanger? If the bike was less than a month old, they probably had one in stock.
There's nothing wrong with REI bicycles, or their service. And derailleur hangers don't shatter. Your story is bogus and a transparent attempt at trolling.