You have a legal right to be paid for the work you did and materials you provided, pursuant to the terms of the agreement (preferably written, though oral/verbal contracts can also be enforced--they are simply more difficult to prove). If the client does not pay, you can sue him/her/it for the money--that's the only way to get it; there is no government agency, for example, including the police or the attorney general, who will get it for you. For an out of state case, you'll have to sue in "regular" court--not small claims. You are advised to retain an attorney to help you.