Google has been making some massive changes to the search engine and related stuff specially this year.
Google has de-indexed all sub domains registered at co.cc (Free + paid domain provider)
The reason for de-indexing co.cc domains is majority of sub domains being spammy and have illegal content.
As Matt Cutts said:
This article reminds me of a Google webspam point of policy that I’ve been meaning to discuss for a long time. First, a definition: a “freehost” is a domain that will let anyone register a site on that domain. There’s lots and lots of high-quality freehosts out there (wordpress.com comes to mind).
We absolutely do try to be granular, but I wanted to mention that if we see a very large fraction of sites on a specific freehost be spammy or low-quality, we do reserve the right to take action on the freehost as a whole. I think most savvy search/SEO folks would understand this completely, but I figure it’s better to over-communicate than under-communicate.
So first of all get a top level domain for your important domains and secondly don’t spam to avoid getting blocked or deindexed by google from its search engine.
Checkout free co.cc alternatives if you still need one.