Should I Give Up, Or Should I Just Keep Chasing Pavements Even If They Lead Nowhere? : Part Two

The representative from my management company responded to me, acting like I insulted him personally by advising that I plan to file suit if he doesn't refund the full amount. He said he was shocked and hurt that I would threaten him without giving him a chance to respond after we've had such a good relationship. Is it cynical that I think his shock and hurt are an act? As I understand the situation, there is a dispute over $150 that is currently in his possession. I think he should give it back to me, and he thinks he should keep it. I asked him to return it to me, and he indicated an unwillingness. That brings us to the end of what I personally can do to get him to give me back my money. He has the upper hand by virtue of the fact that the money is in his possession. If I ask him to return it, and he declines, then there isn't anything left for me to do except accept the money is gone or bring in a third party to resolve the dispute.