Item sold on the net

In december 1999, i put an add on a internet site for Radio control fans like me. I have an engine for sale and i put my add on this site . On december 9, 1999, i received a email from a guy named Cliff Moris, 1435 Eats, Kramer St. Mesa Arizona, asking me if i still have the engine for sale and that he is interested to buy it. I tell him i have it. I ask 450 $ US for it. We deal a little and i sell him for 450 $ US and i pay shipping.He was supposed to ship the money at the same time. Since that time, i cant join him on email nor on the phone. He filters the calls with answering machine. I sent him dozens of email and i never get any answer. I know he received the engine but i am still waiting for the money. In the radio control world, everyone is like a big family. Everyone trust eachother. I just hope somebody will put this man at his place and make him pay me. I am the Quebec MAAC zone director, the main R/C association in canada. I hate to have to tell such a story to many friends that make business every day in the US. Please, help me. Richard Biron