What happens to your Spotify account if you delete/deactivate your facebook account? I made the mistake of linking the 2 when I first joined Spotify in my haste to listen to music.
However! Spotify support were great, they offered to migrate all my playlists from the old account over to the new account. No guarantees they could do that now with everyone deleting their FB accounts at once, but I was really impressed with the friendliness of their service. They pretty much created a customer for life out of me from that support experience.
You will need to contact Spotify support if you deactivated Facebook prior to disconnecting from Spotify.