Originally Posted by CaptainMiles

I agree that UA is 100% at fault here and should provide full compensation. And I worry that OP's apparent travel naiveté will lead to OP not taking the right moves to get compensation from UA. ginanellis, you have been given some very good advice here about shortening your letter, making it to the point, and complaining to DOT. Follow it.

But one thing strikes me as odd in this story. OP says "The only thing she said was we could try and fly to San Francisco and see if they could re-route us somehow through another country". They should have taken this offer.

OP was as PHX early for a 7:45 am flight. OP does not live very far from the airport (we know this because OP was back at home at 7 am). The only CA flight SFO-PEK on 5/9 was CA986 at 2:50 pm. So OP had some 4-5 hours at SFO to sort this out. It seems that OP should have taken up UA on its offer, even if that meant collecting bags and rechecking at SFO. Plenty of time for that.

Then after OP got home and called Air China and learned no visa was needed "I looked at the clock only to see that our flight would be leaving to San Francisco in the next 15 minutes. It was a little to late for that information." Sure, it was too late to make the 7:45 flight, but there are many many PHX-SFO flights, by UA, US and WN. Specifically, even UA had UA5603 leaving PHX 09:53 arriving SFO 11:47. Why not head back to PHX, confront the UA agent with the info from Air China, and make this flight?