Thinking about this some more. I would call up / email, and ask to speak to whoever evaluated your tests. It is fair game to want to know what was done wrong, and what the proper solutions are. That should kill your curiosity, and show what the real deal (or deceitful game) they are playing is.
Sorry you had to go through that mate. There are plenty of jobs out there, hell, if I was you I'd work remotely :-)
JK, but yeah the thing with the three interviews also bugged me, however I just went with it.