Oddly enough, online, UA is offering me an upgrade on their leg. In the meantime, I filed all the complaints.

The BBB one elicited a response from Orbitz customer relations that, of course I could change my flights to the same or lower fare codes, and if lower, I would forfeit the difference (not a question I asked, but fine with that). So I tried calling in again, and was told I could not again (after once against pending a lot of time on hold with an agent, who called AC's desk and they would not do it, and then with a supervisor, who could not make the change, so said any other cheaper flights must not be available, which of course was not true at that very minute from AC and Orbitz' own websites, and then hung up on me). I reported that interaction back to BBB. But I am probably more interested in what Amex and the DOT say.