Originally Posted by
vinonobile
..Arriving in IAD I passed immigration and customs quickly and reached the gate of my original flight and it was still open. I was denied boarding, because I was not on the list anymore. Complaining on the spot didn't help as the flight was already full..
LH is not in charge for that segment (even though they created the problem). You had a boarding pass and hence were entitled to transport if the flight was still open. Hence this is an IDB situation and you should file it as such with the DOT if UA refuses to compensate you.
I'd simultaneously push for LH compensating you for not fulfilling their contract of travel, especially as it was sold as one flight number as you mention.