I have the same experience right now - but the app won't go online! And consequently my offline list can't be activated again.. But worst is that it won't go online. Everything else works fine including data traffic throught both EIFI an 3G..
I also have the same message and I my checked account status which says I am paying for a premium subscription, but I cannot listen to my playlists. I've already made my playlists available offline and it was working fine yesterday so I'm not sure what happened. Also I have wifi at home and even when I connect my phone with wifi, it says I'm offline..Is there no number to call for help??
There is no number to call for help or any kind of customer service of any kind. You have to ask the "community" for help, you cannot speak with Spotify team members directly. You cannot even post to their Facebook wall.
The card I used for my premium membership expired, and after that I was unable to access Spotify on my mobile (it just stayed in offline mode). I updated my card, but my Spotify would never go online on the mobile.
I tried everything and nothing worked.
Finally, uninstalled/re-installed Spotify my mobile (Galaxy S), was prompted to accept the terms, and then I could see Spotify again. Plus all my playlists, downloaded music and what not came back without issue.
Seems obvious, but thought I would share.
You may just have to re-install Spotify on your mobile.