A stranger is using my spotify!

[Mackan804]

So I have had spotify for quite some time and a couple years ago I notcied someone had added some strange playlists on my account. At the time I thought it was just one of my friends who was playing a joke on me becuase I had forgot to log out at their house or something. A couple of days ago however I noticed that some of my playlists had been removed including my favourite one where I have collected all the greatest songs I know. I would like to know if there is a way for me to see which devices has access to my spotify and how to prevent them from using it. And is there anyway to restore removed playlists?

[Mackan804]

I think it might be this person who is calling himself Ed Edd Eduard because whe  my old playlists dissapeared a new one appeared named only playlist and made by this guy. Somehow I am also his only follower and I don't remember ever following this guy. Any help?