Booking with someone like Expedia you get the worst of all possible worlds.

As far as the airline is concerned you are someone who booked through a travel agent, and that makes you the travel agent's responsibility, not the airline's. (Some airlines are worse than others in that respect... if you select the "I booked through a travel agent" option on KLM's switchboard you get a recorded message saying "Please talk to your travel agent. Goodbye")

The problem is that Expedia isn't really a travel agent - they operate with a travel agent's licence, but they really just see themselves as a booking site, and customer support is virtually non-existent. And it's got worse over the years.

So - you're really caught between the devil and the deep blue sea. For the airlines you're a travel agent customer, but your travel agent doesn't see itself as a travel agent.