While it is frustrating to have a seller back out of a deal at the last minute, it is way overboard for you to vent your anger in such a manner.
Making personal attacks and name calling are a violation of CS guidelines, so take this post as a warning from the mods and admins.
How do you think a post like this would help you in your next purchase? Calling the seller immature and childish does not really portrait yourself as a mature grown-up. Have you considered what message you are sending to other sellers about yourself?
Joseph's 30D is not the last one on earth. Hope you get a better experience on your next purchase.