Get a written contract that contains all the details of the job to be performed. The buyer has the right to cancel a home solicitation contract or offer until midnight of the third business day after the day on which the buyer signs an agreement or offer to purchase. All contractors are issued pocket licenses which show the type of trade for which they are licensed and the expiration date of the license. If the person says he or she is representing a contractor, but can't show you a contractor's license or HIS registration, then call the contractor and find out if the person you are dealing with is authorized to act on behalf of the contractor. Deal only with licensed contractors.
Consumers have very little, if any recourse against unlicensed contractors.
You can do more to protect yourself from problems with contractors than the Contractors State License Board can do to help you after you've been harmed. Select a reputable and qualified contractor. Negotiate a clear contract. Prevent disputes with the contractor. Resolve disputes when they arise.