Phone's Been Hacked

I recently had an argument with my roommate and now I think he's been in my phone. When I'm in Spotify it'll shuffle, stop then play other songs, after I turned Siri off it popped open for a split second and my maps activity has places I've never been. I've activated some Google security measures and turned off a lot on my phone and gone to private session on Spotify but this dude with all his laptops and old phones in the house who never leaves the house is creepy anyway. What anti hacker security measures can I take?