We recently hired a car from Hertz via Auto Europe
I think it is necessary to advice anyone hiring that the same credit card which was used for the booking must be presented at the rental office.
We had a problem in that we booked and paid for the car before we left home. When we arrived to pick up the hired car the credit card would not work. It needs to be presented again for security deposit. Hertz were very good in ringing our bank in UK but the card would not work. In the end we had to request Auto Europe to cancel booking and rebook with different credit card. After 2 hours at rental office we eventually got sorted out. Hertz were very good in letting us use their phone to make calls back to UK.