I can see your confusion. Your Hotwire confirmation said you had the car for four days. Hotwire also says it uses a “24-hour billing cycle” to define a single rental day, according to its site.
You consulted the Hertz site, and it more or less agreed. It defines rental days as “based on 24 hour periods commencing at time of pickup.” Additional days apply if the rental is kept longer than specified, with additional days beginning after a 29-minute grace period.
As far as I can tell, the problem was the “specified” time period of your rental. While you were entitled to keep the car four full days, you shortened your rental period when you finalized the reservation and indicated that your return time would be earlier than the fourth day.
Car rental companies are getting stricter about late fees, which is understandable. When a vehicle isn’t on the lot, it can’t be serviced and rented to the next customer, and that costs the company money. But charging $134 for an extra hour seems unreasonable.
I notice that you made several calls to both companies to try to get this fixed. The best way to address this problem is in real time. After you see a surprise charge on your rental receipt, find a manager and voice your concern. A supervisor often can zero out your invoice. Failing that, I would send Hotwire a brief, polite email, as opposed to phoning. When you finally sent a note to Hotwire, it acknowledged that this was a “billing error” and refunded $34. It isn’t immediately clear why it didn’t reverse the entire charge.
I contacted Hotwire on your behalf. A representative said that Hotwire guarantees the quoted rate only for the prearranged length of the reservation – until 5 p.m., in this case. The agency decides if, or what, it wants to charge for any extension on the rental. Hotwire details how to handle rental extensions on its website: www.hotwire.com/helpcenter/cars/after-booking/reservation-changes-cancellation/extend-or-return.jsp.
Hotwire agreed to a refund of the remaining $100.