ISP blocked due to abuse?

Well, it seems today that I'm now unable to post anything over at the 4chan imageboards, otherwise I get this message:
"Posting from your ISP has been blocked due to abuse. [More Info]"
I can still browse the site, all the images and threads load fine, I just can't post. What gives? I've never posted spam or porn.

Venezuela here.

I recently moved, so my ISP changes. I was Intercable (dat 10mbps) but now im forced cantv for now.

Why do they think they have to block the whole ISP for spambots? I manage websites as well and I know for sure there are better ways to handle this. All this proves is laziness and just carelessness. A good majority of Venezuela likes 4chan believe it or not. IP range ban the spambots, but do not ban the whole ISP.