HAHA... try asking a similar question to any other rental company and see how long it takes them to reply to email.

Why didn't you just call the location if you need the response in a certian amount of time? Hertz even says it will takes 1-3 business days for you to get a response in their automated reply.

BTW, I think the info you're looking for can be found at this link:

https://www.hertz.com/rentacar/speci...jsp&Category=D

Hertz.com > Special Offers > Hertz Offers Discounted Parking in Manhattan

That took less than 20 seconds for me to find just clicking around the site.