I agree with giving it time. Our human nature tends to fill voids with negative material. Things happen,not in our control sometimes...he may be out of town or in the middle of a family crisis. I would give benefit of resonable time. Deals done with an internet "handshake" are always vulnerable. We require a credit card number or 50% deposit before starting custom milling work. Not so much to protect the time and material investment, but to establish the level of "seriousness" and "commitment" of the client.
I recently sent three unanswered emails to a knife show promoter. I really wanted to do this show, but not getting the "courtesy" of a response if only...."Sorry, sold out", I was prepared to fire off an email saying "Thanks, but no thanks", if this is your public relations. Finally, got a reply and the promoter had been out of town and "Yes, please do our show". I felt pretty small.