Dear Friend…
I'm sorry you had so much trouble this morning attempting to secure a hotel reservation for this year's Comic-Con International. I'm sure you're telling the truth when you say that you logged on and/or dialed in at the appropriate hour. I can't explain why the rooms were all booked, seemingly within minutes, while you were on hold or waiting for some webpage to load or getting dumped off the line or whatever the hell happened.
I'm also sorry that there's nothing I can do to help you except to suggest that more rooms should become available at some point, both through the convention's booking agency and directly through the various hotels. The hotels, for their own purposes, hold onto some rooms until closer to the con dates. I know that doesn't make sense from your standpoint since you're ready to plunk down cash right now for one…but they're not worried about not selling those rooms. They are worried about not having rooms for important guests and others who do a lot of ongoing business with the hotel. There are also comic-congoers who make multiple reservations, or book more rooms than they'll need, and some of those may become available in the coming months.
Keep looking. You may not be able to stay within walking distance of the convention but you should be able to find a room somewhere if you remain ever-vigilant. It's maddening, I know, but look at it this way: It'll be a great convention and once you get this messy lodging problem settled, you'll forget what a hassle it was and you'll enjoy the heck out of the con. I know I always do.
Your pal,
me
P.S. I expect to be moderating my usual roster of a dozen or more panels at the con. If you can't find a place to sleep in San Diego, come to my panels and sleep there.