Not that I don't think he shouldn't be harassed (hell, he should be strung up
) but we're not the ones to do it and I think you should be worried about possible legal action should he take exception to a bunch of people from this site deciding to take you up on your request. You should be 'harassing' him with the law but unfortunately it sounds like your arrangement means there's little you can do other than wait for the late checks.
It might be worth it to get a trailer and simply go get it.
What a complete drag, I feel for ya.