First off, I feel your pain! I had the same thing happen. I am a Premium member also. Went on my mobile phone app. and it suddenly would not let me use Spotify, even though I had it working fine the day before! I had not logged off. Nothing different than I had been using it like this yesterday and for a while.
Spotify suddenly Made me log in, since it somehow got logged off, and not by me or anyone else I know. No one else has access to my Premium Spotify account.
I tried to log in - it wouldn't let me. Went online on my PC, logged on no problem. Still problem with Mobile. I had used it last with the Offline feature. That was so that I didn't used up my mobile Data. I had used that for a while like that, no problem!
So, since that (offline mode) was on, I was suddenly not allowed to log in! I couldn't even log in to change it from Offine to ONLINE.
So, I had to Uninstall my Android Spotify app, and reinstall it. That worked and I am now logged in to my Mobile premium access. NOW Spotify wants me to Download AGAIN all of the playlists and albums I had before?!!!! SO BAD, especially for paying Premium customer like us. I do know that the downloading should be done with a high speed wifi connection. So, no need to tell me.
SPOTIFY SUPPORT AND TECH DEPARTMENT - You need to FIX THIS. We should NOT have to Re-Download every single thing that we had downloaded and regularly used, just because your system is screwy and we (your paying customers) had nothing to do with your error!
At the very least, you should Refund one month's Premium charge to All paying Spotify members who have had this problem like me and anyone else from today and other days when people had the same problem. I hope that we get a decent answer to this comment from the Spotify "customer service" department.
Fingers, toes and eyes crossed!