When I try to log into the spotify desktop app or the website I have to use the username that they gave me(some random set of numbers & letters), or my email. When I am logged in, it shows my username as the one I have chosen, but I can't use it to log in. I also don't have facebook and I didn't sign up with facebook.
If you want a real username, you have to create a new account on iOS (maybe Android also works), because there you can set a username, and write a tweet @SpotifyCares, they can transfer your playlists and stuff to the new account.
EDIT: It did prompt me to enter a username after I submitted the reply the first time. But I believe that's for the community side. Not sure how closely the main account and community are connected.
