Customer Wants $700 Back Or Is Threatening To Sue.

We worked on a customers truck about a week ago and one of the mechanics that worked on the truck probably got distracted and didn't tighten correctly a shock bolt. The customer called me a couple of days ago telling me the shock came loose 10 minutes down from his house which is about an hour away form the shop. We sent the mechanic with the most experience to re tighten the shock and to make sure everything was done right.

The customer told me he was expecting some compensation so we decided to send $200 with the mechanic so he and his family could eat and to make up with the lost time which was around 4 hours.

This Monday he texted me demanding $500 more or he will take this to court for negligence and emotional distress. To me this feels like he wants to get the most he can out of this and doesn't seem fair, part of me just wants to give him the $500 and be over with it, but it doesn't feel right

BTW this is in the US.