Like said above, a friend lost access to his account. He knows that it was his own fault. That other guy changed the email address and removed the phone number. My friend sent an email twice to steam support, in the second stating what his email address was before the account was stolen and a list of purchases including invoice numbers and payment methods from the purchase confirmation from emails.

The only, probably automated, answer he got was:

Thank your for contacting Valve. This email address is no longer monitored.

Is there anything he can do to get his account back?