Unclaimed means that he refused to receive the letter. You might have your lawyer contact a lawyer in Merced. Going to be expensive...
Come to think of it, that Zavada fella might be the guy who sold me my (now broken and unworking) steering column a number of years ago. At the time he was setting himself up as a distributor for Street Beasts (something I learned after sending him some money). I don't remember the fellas name, but Merced CA sounds familiar.
Best of luck, if nothing else the State Atty Gen. should probably be informed of this fella's business "practices".