The trick I learned in my freelance days came from a designer friend who'd picked this up the hard way and developed his own nuclear option for non-paying clients. Whether it works for a given contractor depends on what the contractor is doing, and so consulting with a lawyer (I am not one) is important. But in general it goes like this:<p>Step 1 is to ensure in advance that your standard agreement includes clauses indicating that creative work you do is not work for hire, that you will, at the start, retain copyright in that work, and will assign the copyright to the client on receipt of payment in full.<p>Step 2 is to go through the normal process; if they don't pay, you send invoices, attempt to negotiate, etc.; make a good-faith effort to resolve the problem.<p>Step 3, if the client still refuses to pay, is a DMCA takedown. You don't have to go to court, you don't have to get into legal wrangling about contract terms, you just get their site taken down until they pay up, which they often will.<p>Of course, they'll give you a bad reputation and you'll never get business from them again, but you'll have food on your table and they'll have learned an important lesson about trying to screw their contractors.