You snooze, you lose. Unfortunately you made a mistake, and, as such, you were treated just like any other passenger who wanted to buy a last-minute ticket. How is CO wrong here? They gave you the option of spending about $150 for 2 award tickets, but that still wasn't satisfactory to you. I find your logic inconsistent. Seems to me that you're ticked off that they didn't just rebook the whole itinerary at no cost to you.