That's a really terrible situation to be in. I will be the first to admit that carrying three carseats through the airport, through security checkpoints to the gate isn't practical. Not to mention the fact that your wife was already dealing with traveling with the 3 children. I agree that you definately deserve either everything returned to you promptly, or compensation for the items lost. I don't believe you are in titled for a "refund for ruining our Christmas". Each traveler takes a certain amount of risk when checking baggage in. Unfortunately United made a HUGE mistake this time. Here's to better experiences.