First, Can't believe you turned down first class. Should have accepted the offer. It was fair. Arrive home 2.5 late, who wants to return home from vacation anyways.
Second, after accepting the offer come home write a nasty email get some miles and vouchers and call it a day.
Third, aircraft changes happen all the time. DOT and FFA won't do anything, time to relax and right that email already.
DYKWIA at its best and no status I love it. I want first classes tickets, you were offered first class and said No.