Logged into the 'Zuzuche' website in China to pre-book a Mercedes-Benz C-Class four-door five-seat car and already paid (rental prices vary by car). On July 18, 2018, when picking up the car at the car rental counter in Frankfurt Airport, the German staff told us that no Mercedes-Benz was available and offered a BMW 3 Series four-door five-seat as an alternative, showing it on a computer screen. After confirming multiple times, we agreed to accept the alternative. Additionally, the staff tried to upsell a Volvo SUV, which we declined. When we went to the parking lot in Frankfurt Airport (about a ten-minute walk) to pick up the car self-service, we found it was actually a Skoda four-door five-seat. We returned to the counter to inquire, and the staff again said no Mercedes-Benz was available and only the Skoda was offered. We sternly pointed out, 'We rented a Mercedes-Benz as shown available on the website and paid for it. Therefore, the company should provide a Mercedes-Benz or give a reasonable explanation for why not, obtain our consent to provide an equivalent or higher-class car, and assume corresponding breach responsibilities. Additionally, claiming falsely that a BMW 3 Series would be provided is an attempt to deceive us. We demand a reasonable explanation and solution.' The staff then took out a key to a Mercedes-Benz from a drawer within two minutes without explanation. We successfully retrieved the car ourselves (a 2017 Mercedes-Benz C-Class 180 four-door five-seat car). Upon inspection, this was the only Mercedes-Benz in the dedicated parking area for the rental company at Frankfurt Airport, and it was a new 2017 model.