We are ticketed in FC on ORD-SFO in July on a 777, which according to Seat Guru is a 2-class cabin in the US market. Our original seat assignments were 4A&B. I noticed today that our seats are now N/A and called United 3 times and got 3 different answers.

The first answer I got was that they weren't allowed to assign seats yet and it was listed as needing to be assigned after we got to the airport... which made no sense b/c we already had seat assignments before. She couldn't give me an answer as to why they were suddenly unassigned and wouldn't let me speak to her supervisor.

The second answer I got was that FC was full and they had no seats left to assign but that we were confirmed on the flight and should have no problems getting a seat. I asked if it was overbooked and they said no and I asked why I couldn't get a seat assignment then and they said b/c there were no seats to give. Then I said that if it wasn't overbooked there should be seats available to assign. We went round and round. I asked to speak to his supervisor and he then decided I needed to talk to someone in International not Domestic b/c technically our itinerary has some international legs (although not that particular day or leg of the total journey).

So I called International. This last, and most detailed, answer was that the plane is now a 3-class cabin and the 4th row is now considered Business Class. Apparently when it was a 2-class cabin there were some people who were really supposed to be in BC but were put in FC for that leg of their itinerary. Now that it's 3-classes their seats are considered FC and they need to be moved to BC seats. We OTOH were assigned seats that are now in BC but I was told we can't move into FC seats until those BC people have been officially downgraded and the seats are freed up.

Do any of these answers sound legit or am I being fed a series of lines here?