Go to
http://www.mtu.com/kb/support-center.htm
If you have not used this before you will need to register, but you can use the same registration you use for the forums or your store account. The security database for the Support Center is not the same one used for the store accounts or the forum. Once you have registered, login to the Support Center and submit a ticket.
If you wait for MTU to find this post it could be several days before they get to it. Be sure to include in your ticket, the email address you used to purchase Hoster so they can find your account.