The staff had very heavy accents, which made communication difficult despite their generally good attitudes. There were about 3 people in front of us, and we waited in line for half an hour. The most serious issue is that this Hertz location in Madrid overcharges customers, so be cautious. We picked up the car a few hours earlier than scheduled, and the staff used this as an excuse to charge us for an additional day (despite us already having prepaid the full amount). Initially, we thought the extra day displayed on the receipt was just indicating our rental period, but the staff never explained this issue, nor did they tell us that picking up the car a few hours early would incur an extra day's charge. We could've waited. Furthermore, we purchased their super cover insurance (which comes with an additional 21% tax), and they included the extra day's rental fee in the insurance tax calculation. When handing over the car, they told us that only the insurance fee would be deducted, with no further explanation of any additional charges. When we followed up with the rental platform, they initially said, 'Hertz over there said you were charged for returning the car late,' and later changed their story to, 'You were charged for picking up the car early.' We rented the car for approximately 81 hours, less than four days, but were overcharged by more than 90 euros. We've rented from Hertz before and never had such an issue. This time we've paid for a very bitter lesson. A severely bad review.