Is it in the ML system? There are a lot of "For Sale By Owner" companies that are licensed by the State of New York as a Real Estate Broker but do not put the listing in the Multiple Listing System or, put it an as a commission to a cooperating broker for $1. If the seller does not want to pay a commission, the broker is not violating any law as long as it is legal and the seller has informed concent. If the house is listed in the multiple listing system and when you call on it you do not deal with the owner directly but a licensed agent or broker, they need to provide you with an agency disclosure in writing informing you that they are representing the seller exclusively and you are entitled to full representation by an agent/broker of the buyer. If there was contact by phone, in person and money was discussed, that agent may have violated State law.
If you feel that your rights to full disclosure were violated or, you are being misled contact the NYS Department of State: http://www.dos.ny.gov/licensing/contact.html
They could send an investigator. You may also have yourself or someone else call, say you want to see the property or want to make an offer and see how they handle it.
Your agent's broker may also file a complaint with the local Real Estate Board if they feel an Ethics rule was violated. This in not about commission though, it is about representation.
Good luck my friend.