funny my wife offered to do the exact same thing almost and call him at home ( found the # online! ) and really lay it on him how he's stealing food from our kid's mouth.
That being said, for me it doesn't make a lot of sense to sue someone without money. That is just throwing more time and money down a hole. It was more productive to learn from the experience, adjust client engagement process to reduce the chance it'd happen again, and move on.