First, they extended a trip of less than 4 days to 5 days, and the official confirmation receipt was higher than the booked price. They insisted I sign it first before I could raise objections. When I requested intervention from the car rental platform, it hardly made any difference. Only after continuous demands did they change it back to 4 days. During a vehicle inspection, I was dissatisfied and asked for an upgrade. They only mentioned a $15 daily upgrade fee but didn't inform me about an additional fee or tax of about 200 yuan, which is outright robbery.