Hertz - Complaint letter - where to send?

I need to write a complaint letter about two incidences with Hertz. One was picking up the vehicle at LAX and the other was about the return to SAN. Where do I send it?

https://www.hertz.com/rentacar/customersupport/index.jsp?targetPage=contactUsTypeSelectionView.js p&leftNavUserSelection=globNav_9_1