These are the possible scenarios that may have taken place and how to fix them:
1. Spotify created account (primary) + Facebook account. -Their screenshot will have their FB photo in the top right corner with 'SpotifyFree' at the top and no playlists. These are easy to solve. All the user's playlists are in their Spotify account. They should sign out and sign in with their Spotify username (not their email address). It's best to recommend linking their FB to that account to avoid future confusion.
2. Spotify created account (primary) + Facebook account (Premium) - They have upgraded their non-Primary Facebook account. Their screenshot will have their FB photo in the top right corner with 'Spotify Premium' at the top and no playlists.
3. Spotify created account (Premium) + Facebook account (primary) - They usually use their Facebook account and have built all playlists there. However, they forgot they made a second account and have upgraded that one.
If you're on Premium, try signing out and back into the app.
If it says Free, check the receipt we send to your email inbox. Make sure you're signing in with the username on that receipt. If the username on your receipt is a 10 digit number, please sign in with your Facebook login details.