I had an account at the dnsau.com.ru and there is no longer the shell to access my email. Is there a way I can retrieve the email sent last week? Please advise.

We had to close it down due to problems with the 3rd Party who was supplying the webmail. Go to http://www.postmastergeneral.com.ru and select a domain name that you prefer and sign up with it.

So all of my emails are gone?

Yes, I would say that all emails have been lost......