It's not clear what you are actually looking for.

If this agent is looking to appear as your selling agent, and to receive his
usual commission and then keep 50% and pass the rest to you; and that's what
you indeed negotiated with him when you contacted him, only without the
numbers; then, I would say, what he says makes sense, and from the ethical
standpoint, you indeed have to sit down and negotiate with him.

But if he is expecting something out of your pocket, not being your buyer's
agent, then I wouldn't pay him a dime. He did the usual RE agent's job; what
you finally chose was not from him; tough luck, but nothing unusual for a RE
agent. Even the fact that you indeed worked with him, does not mean much:
during that very work, you easily might get disappointed in him. If there
were no obligations, then there are no obligations. If he is trying to
pretend that he did what he did not, and that you are obligated to pay for
it, feel free to send a letter of complaint to the entity where he gets his
license -http://www.obre.state.il.us/CONSUMER/FORMS/cnrffrm.htm, plus any RE
associations he is a member of, like realtor.org and http://www.nsbar.org/nsbar-elinear/public.htm.
I don't think their interest in maintaining the ethics of their members goes
far beyond the attempts to sell courses and brochures about the ethics to
those members (though I may be wrong), but at least the agent will have to
write some lies in response, and be somewhat scared - which is important to
you regarding the rumors you are afraid of.


regards