Accident, what can my friend do?

[rondocap]

So my friend was in a parking lot, and parked - this large SUV was backing up and slowly backed up into the side of his car. It left a dent, maybe like 5 inches across. He decided to be a good sport about it, and only took the guy's first name and phone number. Damage was around $300 or so, I think.

Now..he called the guy and the guy answered and said he'll meet up with him to give him the $300. What happened if the guy decides not to pay or show? Is there anything he can do? I don't think he took down the license plate information or anything, just the phone number.

Is he screwed, or can he track the guy down with his cell #?