Can't log in using username or e-mail address, only using 10-digit account number

[belltown]

I'm a Spotify Preium member.

When I log in to my Spotify Windows client, I can enter either my e-mail address or my 10-digit account number as the username. However, when trying to log in to the Spotify Community or the Spotify web player, I can only enter my 10-digit account number as the username; it will not accept my e-mail address. Neither the Spotify WIndows client nor the web player nor the community login will accept my Spotify username: 'belltown'.

Why can I not log in to any Spotify service using my username: 'belltown'?

Why can I only log in to the Spotify Community or web player using my 10-digit acount number and not the e-mail address that I use to log into the Spotify WIndows client?

[Stupify]

This "account number" is, in fact, your username. If you remember registering an account called "belltown", you have created a second account using Facebook. Facebook-created accounts get assigned a username consisting of random numbers.

The Spotify login process works like this: If you enter an email address on the username field, it is interpreted as a Facebook email address and, thus, Spotify will attempt to log in using Facebook login details. If you have logged in by typing in your email on the login field, it's likely you have accidentally created a second spotify user through your Facebook account.