I would bet that the ticketing airline records them as the travel agent who sold the ticket. That doesn't mean they're going to provide great service - or any service, as it seems was, sadly, the case for you. But as a lot of the posts on the Alitalia LCA error will attest, when it comes to an airline refusing to change things on the grounds that "the travel agent [Orbitz] made the booking, so THEY have to make the changes", you will find that at least the airlines consider Orbitz a travel agent. (I know that this eventually changed, but would argue special circumstances in that case which prove the rule otherwise).

The OP of this thread may find that Orbitz also tells him/her to go pound sand when called, but I would still suggest giving it a shot.