FWIW, to follow up with my own experience. After numerous emails back and forth, including a few pings (due to lack of response), more folks getting added to the to line by Air China folks, and the San Francisco Air China office being involved + me having to send various materials (e.g. passport (I redacted some info), boarding passes, itinerary, etc.), I received a check for $50 USD today.

It took awhile, but it was better than nothing.