Why must the customer do all the leg work here? I would provide Hertz the RA# and have them call the location.
One tip: when faxing it's always good to have a specific name to which the fax is addressed. It will often get quicker attention than a fax addressed to Customer Service (or whatever). The latter just gets stuck in a pile and they get to it when they get to it.
What the hell are you talking about?