I made a Budget prepaid reservation and subsequently found a lower rate on the same car/times. I realize there's a $50 fee to cancel my reservation, but I keep seeing mentions of folks getting refunds for reservation modifications that result in a credit. I've tried to modify the reservation a few times, changing the pickup time slightly, etc, and the page will show the old prepaid rate vs. the new lower rate, as well as the credit that will be due to me, but when I click through to confirm, the lower rate and credit amount disappear and the prepaid price shows up again. Any ideas?