If payment for your services was not conditioned upon their receipt of funds from the closing. I would say that they probably owe you the money.
One further word of caution, if you are operating as a corporation or LLC you may need to hire a lawyer to collect these funds unless your state allows you to act on behalf of the corporation or LLC in a civil action. In Connecticut this is permitted in small claims court but not in the Superior Court. It is an unauthorized practice of law.