I opened my Spotify iPhone app and saw that i was following about 20 playlists, all by the same user. I didn't follow these myself. I logged out of all devices and changed my password, both on facebook and on Spotify itself. I also unfollowed all of the playlists.
This morning there are 20 similar, but differently named playlists that have appeared, which i didn't follow myself. They are all by Captivate Music.