I also do not know either party.
But the excuse of "the photos were there, not my fault you didn't see the broken leg" is completely unacceptable. How about "sorry, that animal had IBD when I got it, too bad you didn't specifically ask if it had IBD or not before you bought it", or "yes, the animal had mites, sorry you didn't see the little specks but they were right there in the photo, deal with it"? Just as bad, in my opinion.
In my opinion, if an animal has an issue the seller is aware of, it should be mentioned in TEXT in the advertisement. In this case - "The chameleon has a broken leg, which can be seen in the photograph".
LOTS of other people are perfectly responsible when listing less-than-perfect animals - such as "has a small scar on nose from an old nose rub but it's healed, it is not visible in the photo" or "snake has a small kink at the end of its tail".
I'd never buy from someone who thought that selling an injured animal without mentioning it (and not TREATING IT!) was a-ok. Sorry, Jesus, but regardless of what other business you get, you probably won't from anyone who views this forum. And it's not vindictive in any way - your attitude towards the whole issue just show you don't have a professional attitude. You may be a great person, I don't know you by anything except what I've read here, and that tidbit warns to mistrust how you represent animals in advertisements. I believe it's called "lying by omission".