I just read this entire thread and am really sorry you got so badly duped by this idiot at this show. Frankly, even with the great advice I do not think s/he could have been saved. My guess is that Will, Chris & Kinyonga all had the same thought but tried to steer you in the right direction.
Chams takes specific care depending on species and are very different from geckos, beardies, snakes, frogs...you get the idea.
Got to all the sites recommended, do your reading, ask questions here and other forums and decide if you even want to take on the care and expense of a chameleon. Also, I STRONGLY recommend you find a vet who has some cham (not just lizard) experience BEFORE you get one. You will probably need one sooner or later - even just for the 2x/year fecal checks.
I hope this guy comes thru with your refund.
check out the link below for websites (many already suggested) as well as vet listing by state. Good luck to you and maybe we'll see you around 
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Chameleon Help & Resource Info
1.0 Nosy Be Panther Chameleon - Cyrus
0.1 Veiled Chameleon - Luna. She's now hanging from her big jungle gym in the sky
1.0 Beardie - Darwin
1.1.1 Side-blotched lizards - Ana and Stan
0.2 felines - Kyndra and Lita
0.1 African Clawed Frog - Skippy
0.1 Chilean Rose Hair Tarantula - Rosa Leigh, Died 4/21/06 
0.1 Goliath Bird-Eater Tarantula - Natasha, donated to science 4/4/06
?.? Pinktoe Tarantula - no name yet