Your Admin@ (organisation) is set as admin@ as it is the master login for your organisation, you can create another user with a different name if you please. 

You CANNOT use your organisation's personal emails as logins for CommBox manage, an email address is required to link to an IT manager. For example, cannot use this email address to log into his CommBox Manage account, he would need to use 'john@schoolname' to log in to his organisation's account named 'schoolname'.