Looking for some advice on how to complain about United giving away my seats. My wife and I recently traveled on United Business award tickets to Europe and back to California. Most of the trip was on a partner airline but the last leg from the East Coast home was on United where we had first class seats reserved. We arrived on the east coast a little late with the partner flight and we still had to clear passport control and customs so I was worried about making the flight at about 8:00 pm. While cursing not having Global Entry we raced to passport control to find it completely empty of travelers and we breezed through. Next, our bags were first up on the belt and as we ran past a United help desk we asked if they could notify the gate that we were coming and to not leave without us. The United attendant checked our flight and said we were fine and no need to call. My wife asked if she would still call just in case but the woman, quite rudely, said there was no need if we just went upstairs and it was just about 50 yards away. We went upstairs to find that the gate was closed and we were told we were booked on the next flight and had to get new boarding passes at the help desk about 50 feet away. I was annoyed and went to the desk and complained as we were not late in my opinion and the plane hadn't left yet. They took my boarding passes to see what was up and gave me new ones for a later flight that got us to California after midnight - not great. Then a United agent came running from our boarding gate and said we could still get on our original flight as we were still in good time, except ... they had given away our seats to someone from economy as an upgrade but there were plenty of seats at the back of the plane! I was shocked and said she could just downgrade those two people and give us back our seats. She said that was impossible now as once someone had the seats they could not be downgraded. I asked if she had failed to notice that we had those seats and she was downgrading us ... but she didn't see the connection. Anyway I refused to accept the downgrade and went back to the help desk to see what could be done, only to find that the seats on our later flight were not together. I asked them to change the seats so we could sit together and they said only the gate people could do that. So we went back to the new gate, just a few yards down with the same United woman from our original flight chasing us saying we can still get on our original flight in coach and they were holding the plane for us, but still only in economy. This whole thing took about 15 minutes, which actually made the original flight leave late anyway. We waited for another 30 minutes until an agent came to the new gate and I asked her to change our seats so we could sit together, but she said it was impossible as a seat cannot be changed in first class without the booked passenger's permission (economy would be OK to change?) I told her our seats were given away without our permission and she said that should not have happened but would not budge on her "rule". In the end a passenger moved to acomodate us sitting next to each other. So, am I wrong in thinking this was worse than being bumped? After all, they left without filling our two seats and I was told the later flight was full so United potentially lost out and we certainly lost out when we got stuck with a lousy car rental at LAX at about 1:30 am and 2 hours late. Was United in their rights to give away our seats and yet offer us economy on the same flight?