So I was booked from hk to sfo on Air Canada today with stopover on business class through an upgrade certificate. So I get to van city on ac008 and everything is fine, and i pass thru the us customs with my 2nd ticket on ac 564. they mentioned earlier there was cancellations all day to sfo because of incessant rain and i saw a few flights were merged an there was a united flight out to sf with a/c code share so i headed to the gate 77. once boarding started, i went to the right side check-in, he ripped the stub, seat 1A, and seemed like he scanned it, then went on board. on the flight, someone was in my seat and i showed flight attendent my boarding pass and she said to sit in empty space beside him. finally, when i get to sfo and look for my checked baggage, its not there and i realized i boarded wrong flight and my baggage was still in van city. and united had no record of my being on that flight so i could have been a terrorist for instance and they wouldn't know anything. my boarding pass was essentially invalid for that flight.

they said they'd compensate me for basic clothing needs, separately arrange my bags to be delivered tomorrow but this seemed such a weird case as the ppl at united said they haven't seen anything like this before and not sure how i could be compensated or any legal action to take. anybody's thoughts or have similar experiences?