Slightly off topic, but I noticed that many others had issues getting Hertz to respond to or even acknowledge emails and phone calls.
I dropped al my business with Hertz last year due to this complete inability to answer calls or emails after multiple issues with Hertz locations in Manhattan. I took my $5-10,000 / year annual car rental spend to Avis and have been much happier with them (although Avis' "rewards" system is a joke).
It's astonishing to me that a company the size of Hertz appears to have diverted all their customer service resources to twitter and expects multi year five star gold members to discuss rental issues in 140 character bursts over twitter rather than responding to emails, phone calls, or letters sent to them in the mail.