Ok, UPS. Contact UPS to make sure they have no record of picking up the shipment. Just issuing a tracking number doesn't mean the Gunsmith actually shipped it. If UPS doesn't have a tracking you have some good advice above. I'd call the local Sheriff, tell him/her the story and ask for a wellness check to make sure the guy is still alive then proceed from there. A visit from local law enforcement might be all that is needed to get the guy moving.
If he hasn't responded by now maybe something is wrong with him.