Regarding email, it's still possible for practically every other mailserver on the Internet to block messages from you,
effectively banning you. That's what happened to OP I believe.
On the second one you might want to look further into that case... people have been frantically going after every possible company that does any business with them trying to get them off the internet, whether that's hosting providers, DDoS protection services, IP allocation providers, upstream ISPs, nameservers, domain registrars, etc.
