From our complaint to Kayak:
My girlfriend and I realized that instead of starting our vacation in Athens, that we should have started in Hungary/Romania. We looked to see if we could make this very simple switch and saw that according to your policies it was possible. When I called, not only did I find out that it was not possible to switch but that the tickets were completely non-refundable. The man on the phone said that we were completely locked in and there was nothing that we could do about it. If we had booked directly with the airlines, we would likely not be in this position. Because we made the mistake of booking with Kayak, one which we will NEVER repeat, we are completely screwed, as your representative so callously pointed out.
They have not responded. Bastards!