It's a damned shame people do this kind of thing. It was more than good of you to accept the first short payment and not say anything on the chance that he made an honest mistake, but to be a total rip off is just pathetic. None of us really like to discuss or deal with the payment part, especially before the session starts, but when things like this happen it's totally understandable.

I guess the safe thing to have done the first time would have been to let him know he was short and either let it slide or give him the chance to pay up, but after one "slip up" I'd have to check that guy's payment in advance. As unpleasant as it may seem, it's probably a good idea for all clients.

Sorry it happened. You're too sweet for that kind of thing to take place.