Have you tried contacting a collections agency?
If I have bad debt under $500 i will first tell the customer that i am sending them to collections and that their credit is going to get screwed up. That rattles them half of the time enough to pay me. The other half I do send to collections. They only take a percentage of the recovery if they win, but it wont cost you anything if they dont get any $$ for you. You dont need a SS # for the customer, the collector has access to that stuff.