Ok, you've tried calling the contractor and he's dodging you. Next step is send a return receipt required letter to him asking for your money back...This starts the paper trail. Be polite and firm in the letter. Say plainly that if you haven't received a response in xx business days (I'd give him 10 business days) you're going to be filing with small claims
Then, contact the architect and outline your efforts to date, ask him if he's seen this action by the guy in the past or if he know's of any reason for this problem. (He hasn't, that's why he recommended him in the first place) but at least you've asked.
After 10 dayss with no response, file the claim...of course, go ahead and fill everything out now, since you know this guy won't respond...but on the morning of the 11th day, the paperwork hit's the court system.
Yes, the guy may not show up and if he doesn't, you win by default...if he does, be ready with your facts. What reasonable expensies may he have incurred in filing your plans? Those may be deducted from your settlement.
If you file the paperwork, make sure to name his business so that you can attach any assets the company may have.