fought of my cousin from using my spotify

few weeks back then, i finally used my Spotify, then i realized the changes, the songs that i haven't listen, its because my cousin used my Spotify without noticing, so i try to make my cousin stop using my spotify account by protesting using the playlist names or cutting off their connection with my account, until one day, my rock playlist just got deleted, angered, i deleted my cousins playlists and unfriend people i dont know, now i finally got in control of my account