If you've ever forgot your password and password reminder is not working for you (because for example you didn't changed default admin email address) - nothing to worry about - you can still change it in HostBill database.
To change your password using SQL:
Login to your HostBill mysql database (for ex. using PhpMyAdmin tool)
Browse to hb_admin_access table
Update and perform SQL Query below:
UPDATE hb_admin_access SET `password`=MD5('mynewadminpassword') WHERE username='admin';