I have been using Spotify free for years.
Some days ago I upgraded to Premium and now my music is gone.
What has happend?
I did not delete my self.
Just head to your account page and click the Recover playlists option. Find the playlist you want to recover, click the restore button,
if that didnt work you can click this link: Contact us to Contact Customer Support if you don't find a solution
Have a great New Year