I created my Spotify account using FB account and unfortunatelly it's not easy to undo. I'm planning closing my FB account but if I do it I will loose access to spotify. I'm also unable to create new Spotify account using my email address as it's the same address that FB uses so Spotify won't let me do it - it says that this email is already used.
So I decided to cancel premium subscription, change my FB email and then open new Spotify account with my own email. Changing FB email was easy but Spotify still shows my old email and didn't update for over a week now.