Were you able to resolve this issue? I've had a similar problem when I booked a flight through Orbitz, with US Airways. Came to the Amsterdam early in the morning, only to find out one leg of my flight was cancelled. Orbitz couldn't help me as it was 3 am in the morning in US, and the girl that was trying to help me needed her manager approval, so she basically told me I have to wait for about 5 hours until it's morning in the US.
After it was all said and done, I ended up flying economy class on US Airways, (although I had a business class ticket) and I chased Orbitz for months. They agreed to refund me back some $300 out of $3600 ticket. So to answer your question, as ticket was purchased through Orbitz, it's best to go through Orbitz only, as they are the ones that have to chase the airline company. More than likely it is Orbitz' fault.
US Airways staff in Europe told me they have had multiple problems with Orbitz bookings.
Just yesterday, I was looking at business class seats with Copa, to fly from Orlando to Mendoza, AR. The ticket was $2600 on Orbitz.com, and my travel agent quoted me $3450. When I told him about Orbitz he went to research this, and told me Orbitz is advertising one leg of the flight as business class, when in fact it is economy class, or Y class. We don't get to see the fare class online when we book, it just says "business" so we assume it's business. Then when you get to the airport there are all kinds of problems.
I refuse to book through Orbitz again.