Under most circumstances, if the price for a ticket you have already purchased goes down, you are entitled to a refund for the difference. This only applies if the exact same itinerary you purchased can now be bought for a lower price with all conditions being the same. If you purchased the orginal ticket on Orbitz and now the exact same flights can be purchased again from Orbitz for a lower price, you should call Orbitz and request a refund for the difference.