Hertz and Priceline DO NOT book a rental car through priceline! Nationwide

My husband and I booked a rental car through Priceline at a decent rate and were very happy since we were traveling on a budget.  When picking up the car Hertz my husband was asked what size car he reserved, and since I made the reservation and he didn't know, he said whatever was pre-arranged.  The agent asked him to swipe his card for incidentals which was not an unusual request.  We pick up our car, continue with our vacation, drop it off without problems.  I check our credit card statement and not only did priceline charge us but hertz did as well!  Upon further investigation, the receipt stated $140 upgrade fee.  After reading other reviews, I see that this is a common trick and they just point fingers at each other.  I am going to try to fight it through my credit card company.