Thanks for your posts here! I've just got an update from the folks at Spotify. The app has been renamed to: 'Spotify Advertising Cookie' and the description has been updated to clarify what this is. Head to the Privacy Center for more information about your privacy.
Also, if you think your account has been accessed by someone else, head to this page on what to do next. Let me know if there's anything else.
Take care! :)