Zohomail business login doesn't allow @

Zohomail business login doesn't allow @

i have signed up for the free 5 user lite edition for my company and have only one account (other than the admin account).

when i try to login with my USER@company.com address, i am redirected to an update account information dialog which does not allow me to use @.

there is no help anywhere - and have wasted an hour already.