To File a Complaint against a Real Estate Broker, you have to Write down and document the offending incident. Before you contact anyone, you need to write up a summary and outline of the incident when it is still fresh in your mind. You must Note names, times and places. After that, Contact the local Realtor association. If you are unable to find the local Realtor association, you should contact the National Association of Realtors. Then, Contact the state real estate department in the state where the incident occurred. If you are unable to locate the state’s real estate board, you can contact the National Association of Realtors for assistance.