I booked a large MPV on the website, and the estimated total cost was more than 4,000 RMB. When I picked up the car at the rental company, they asked for my credit card. I repeatedly confirmed with the staff that the payment had been made online. They assured me that the car had been paid for and the credit card was only for potential additional charges. When I went to the car lot, all the cars of the same series were parked together. The staff directed me to the pick-up area and matched my order with one of the cars. There were 7-8 cars including Dodge, Kia, and Chrysler. There was also a Sienna, and I asked the staff if I could take it. The staff said any car in that row was fine. I was happy and didn’t think much of it since they confirmed the payment was already made online and said I could take any of the available cars. I drove off, but later I found out when returning the car that I was charged an additional 5,000 RMB. They said it was for a car upgrade, which means the total cost was now 10,000 RMB instead of the planned 4,000 RMB. It's really not cheap. If I had chosen an upgrade myself, I'd be fine paying more, but they charged me without my consent. I don’t think anyone can accept this. I hope others are cautious when renting cars in the future. This was my first time experiencing this in my three trips to the U.S.