I spent 13 years as a freelance consultant at my own company, or at small consultancies I worked for. This happened to me a few times. First off, if possible,

I spent 13 years as a freelance consultant at my own company, or at small consultancies I worked for. This happened to me a few times. First off, if possible, you want to stage your contract with multiple deliverable milestones, each associated with them giving you money. When they pay you, you move on to the next stage. It's more upfront work, and more oversight, and just generally more complicated than "I work for a couple of months and then throw the whole thing over the fence, and you throw me a bag of money from the other side". But, the upside for you is less risk and a steadier source of income. For the client, it builds in more opportunities for feedback, including the opportunity to say "I don't want to work with this guy anymore," or "actually, I'm running out of money and I want to pump the breaks", so it reduces their risk as well. I never took anyone to court; I guess I got lucky. I recognize none of this has answered your question. The only real advice I have is that there's got to be a reason they are refusing to pay. If they don't have the money, unfortunately you are probably never going to get paid, even if you take them to court. If they do have money, and are just unsatisfied about something (not necessarily your fault, it's often just a misunderstanding) then I would do everything in my power to figure out what is wrong and fix it. Word-of-mouth referrals are so important to contracting, and often just being really high-touch and communicative with the client—and yeah, occasionally giving them a few hours of free work to indulge their petty whims—can turn an angry client into a happy, paying customer.