You have a couple of options:
1. The agent should be licensed by the Dept. of Real Estate.
2. Not all agents are Realtors, or members of the National Association of Realtors. Realtors are required to adhere to the Code of Ethics (see www.realtor.org).
Depending upon how this agent is affiliated, you can file a complaint with the state dept. of licensing, file a grievance if they are a Realtor, of perhaps sue them in court.