He has much more to lose.
If he has good credit history, having a dent like this is going to screw him up.
He may not be able to get a good loan for closing his next purchase.
Don't be fooled by the CFO title. Many CFOs don't even make much more than the landlords here.
You can write a firm letter yourself, or hire a lawyer to do so.
If he still has his mind, he will be softer once you show how firm you are. Follow the state rental act exactly and keep the clock ticking.
(Collecting money in person like what you described was a bad idea though)