They didn’t de-index multiple domains, they de-indexed just one domain, co.cc. All the other .cc domains were untouched. All of the .co.cc subdomains are owned by the same entity that owns the co.cc domain. Because the owner of the co.cc domain had allowed a large number of scammers to freely use their subdomains the whole domain got de-indexed.
You have two options.
- You can use a 301 Permanent Redirect to channel most of your existing link juice to a new domain. You should retain about 85% of the link juice if done properly.
- You can request a reconsideration from Google. They realized that a few good subdomains would get de-indexed and will reconsider those that make a request.