Berlin-Königssee-Munich-Heidelberg-Berlin

Overall, the car from the rental company was quite good, very new and easy to drive. However, there are a few points: First, my order did not include a GPS, but when I arrived at the airport, the staff didn't ask if I needed one and directly gave me a car with a GPS. They printed a receipt on the spot, and I didn't read it carefully before signing. That's my fault, and I ended up paying 66 euros for the GPS. Second, the return process was very quick. We checked for damages and signed off without confirming the mileage, but I took a picture of the odometer the night before returning the car. I only drove from the city to the airport on the return day, so I'm sure of the mileage. However, the rental company claimed the mileage was 200-300 kilometers more than my record, and I was very upset as I couldn't contest it. Since we didn't confirm the mileage upon return and I didn't sign anything, does the rental company just get to decide the mileage? Third, I had to pay a 92-euro fee for picking up the car at the airport. This was not clearly communicated by either the booking platform or the rental company, which was quite disappointing as it was my first time renting a car.