Am I reading this right?
You bought a coach ticket and were placed in coach. You paid a $400 UG to get into the FC cabin and were bumped out (abviously because someone bought a 1st class ticket) I think by legal right you are entitled to your $400
back for services not rendered and you have right to this refund in cash.
In addition you should be compensated with the one way UG for a future flight.
I would accept nothing less in court.