It either hasn't been turned back on or whoever has it has already restored it, or managed to turn off find my iPhone before you managed to lock it.
Contact Verizon and report it stolen. There's not much else you can do.
Oh, and if you didn't have a passcode set, possibly even if you did, change ALL of your passwords. Immediately. You can't track it if it's deactivated, but if the person who has it has half a clue, you'll never be able to track it anyway. Plenty of people report being able to recover stolen phones, but that's not what find my iPhone was designed for. It was designed to locate lost phones and to give you some method of protecting your data if you do lose it.