A lot of things could happen during the month. For example, your ISP could ban whole .cc domain (crazy idea) or install content filtering software or something else. But it definitely looks like actions of your ISP.
And yes, my previous advice (using special software + socks proxy) can be considered by ISP as a malicious intentions, since this kind of tools frequently used for net hacks (building chains of proxies to foul the trails).
Well, other random advices:
1. Try accesing the PBW by IP:
http://69.81.92.216/
2. Try cgi annonymizer:
WebWarper (it GZips web content so it should bypass content filtering soft, if there is any). If succeeded, use graphic mode. Text mode is broken.
3. As the Last resort - get in touch with ISP support and ask them about your problems.