"Stolen" is a pretty severe accusation, and you've made it specifically against the UPS delivery person. I'd temper that a little if I were you. You have no evidence beyond the missing phone, and meanwhile we have no one's word but yours that YOU didn't steal it.
Report it to the police too. Unless there's reason not to... ahem...
I love how so many people here just assume that everyone is lying about something. Oh, not the things they say. Just everyone else.