I am unlicensed, but a reputable contractor. If a client won't pay me, do I have legal recourse?
Your best course of action is to try to resolve the matter amicably with your client, as your chances for recovery through the legal system are bleak. In most communities, contractors must be licensed to do business and failure to do so is a major stumbling block to bringing a claim in court for breach of contract and winning. Judges are not sympathetic to violators of public policy, no matter how meritorious a claim may be.
In addition, it’s possible that you could be in a showdown with the local government agency that issued the building permit, if your name appeared as a licensed contractor. Fraudulent reporting is a serious offense.
Your best remedy, though, is simply to license yourself before you engage in business to avoid legal problems.