Q: My employer trusted his computer I believe as he has on the music app all my music and when I go into my music app It asks music on this phone or music not on this phone all the music I bought shows not on this phone plus he has known things I have done

I Believe my iPhone has been downloaded by someone as this person has all my music , thet can't get into their iCloud, they have known things that I have not told anyone, all my personal info and memories of events have been deleted is this possible that someone could get my info all of it by plugging my phone into their computer?