I called United again and the rep I just talked to says that I was never on the waitlist in the first place. I said that didn't make any sense because the agent confirmed for me that I was waitlisted for all four segments. The rep says that no, you weren't on the waitlist, and she just didn't tell you. That does not make sense to me though, because up until today, the online itinerary showed nothing beside that segment, and today it's "upgrade request denied". So how could they deny my upgrade request if I wasn't even on the list in the first place?

This has been disappointing because I usually have such great experiences with United.