I'll try to call one of the contacts, and find the owner. Keeping it will make me feel guilty and selling it is no difference from telling the police to come arrest me for my dishonest act. In singapore, if I sell a phone to a shop, they'll take down the my ic number, name and everything so they can track if the phone sold is stolen or what. So my last solution is to pass it to the police. Hope you'll get your phone back!