Since you mentioned it AndrewNYC, here is an update on my lost seat. Turns out that my entire return trip ticket was lost as well! Even though I never accessed this data on-line (I was only looking at the outbound information).

I spoke with a very nice (but handcuffed) agent. I now have a cozy middle seat for my return flight unless I am upgraded. Oh well, at least I got back on the flight (I wouldn't have, if I did not happen to immediately check my itinerary upon landing).
A word to the wise: NEVER view/modify your seat from the CO website. When I called WE CARE, they said as much: "Please call us and we wll be happy to make any seat modification for you".