said by removed:The domain name was never yours to begin with
For what it's worth, nobody really ever really truly owns a domain name so it could happen to anybody. WIPO, DMCA, theft, and old-fashioned forgetting to renew can all lead to a loss of your domain. Sounds like Mailbank was making money off of selling services that used the domain (subdomain, email, etc.) and obviously got a better deal to sell, so who can blame them.
It certainly sucks, and it is kind of shady only giving 10 days notice. I'm sure the actual deal took longer than 10 days to put together, but Mailbank being greedy probably waited until the ink was dry to send notice out.