Sixt's "leave the keys and go" return almost cost me 583€ in false charges
I rented a car from Sixt at Munich airport for four days. I took unlimited mileage and all-inclusive protection for peace of mind. Getting the keys and car was easy and fast at the airport, and everything went as planned during the rental period.
Returning the car was made to seem easy too. I filled up at the nearest gas station and drove to the airport rental return area. I assume the car's license plate was scanned as I drove in, because I got a message from Sixt saying: "Welcome back! Please park, leave the key in the car, and you're good to go. Your return receipt will be emailed shortly. Safe travels!" So I did exactly that; parked the car, grabbed my belongings, and left the keys inside. The car was parked there a full 50 minutes before the rental agreement even ended.
I got a real surprise when my plane landed back home and I saw the receipt Sixt had sent me. They'd charged me 583.89€ (more than the actual rental cost) for an empty tank, late return, and excess mileage. For example, Sixt charged me 449.25€ to refuel a car I had filled up just 10 minutes before returning it. The recorded return time was about 2.5 hours after I actually returned it — at which point I was literally sitting in my seat on the plane. It also struck me as odd to be charged for excess mileage when I'd already paid extra for unlimited mileage.
I started looking for a way to dispute the charges. I couldn't find a proper complaints process on their website, so I messaged them on WhatsApp, which was the only contact method listed. After getting past the AI bots, I finally reached a real person, who just said I'd been charged for refueling because the car was returned with an empty tank. I never heard back on whether the issue was being looked into. I tried following up through the right channel but got nothing except a bot thanking me for my patience while it "transferred me to an agent."
Eventually I got an email from customer support that just said, "Upon review, we can confirm that the additional charges..." followed by a breakdown of the same charges. I replied with photos, receipts, and a detailed explanation showing all the charges were false. After that, I finally got an email saying they'd processed a refund, which I should expect to see in 3–15 business days.
This whole experience makes me wonder whether Sixt is genuinely trying to streamline the rental process, or whether "contactless returns" are just a new way to tack on extra charges. None of this would have happened if there'd been someone there to check the car with us in person — it's a lot harder to falsely claim a tank is empty when you're standing right there looking at it. A two-minute in-person check would have avoided all of this. Instead, it took three customer support agents, hours of my time during multiple days, and Sixt holding onto my 583.89€ for up to three weeks.
Has anyone else run into this? Any tips for avoiding this kind of hassle with airport rentals in the future?
TL;DR: Returned Sixt rental as instructed (no staff check, just an automated "all good" message) — got hit with 583€ in extra charges (full tank marked empty, "late" return while I was on the plane, mileage fee despite unlimited mileage). Took many days and photo evidence to get refunded. Contactless returns = easy way for them to add fake charges?