Need username(phone number)

Hambrise,

any of the phone numbers belonging to account can be used as a username. It can be not only number belonging to particular extension but also main company number if a user provided extension number along with main number to login. It can be also email address. So I don't see much sense of displaying particular phone number which was used to login. In our own sites we usually display first and last name of a user and also main company number and user's extension number.