When is a username not a username?

This week I bought a new mobile phone and moved networks to Vodafone.  I signed up for access to view bills online but 24 hours later when I tried to log back in I couldn’t for the life of me remember what username I’d chosen.

I tried all my usual combinations of usernames and passwords, searched my email but to no avail.  Then it struck me, the sign up process asked if I wanted to use my email address and I said “of course – I’ll never forget what that is!” yet logging in gives no clue that this is a possibility:

Vodafone Username

So web designers, if you accept email addresses for logging in, please don’t label the input “username”, and while you’re at it, examples of acceptable input is a really nice touch too.