Unclear charges for insurance - Environmental protection fee?

I rented the car from Europcar at Munich Airport. Since the airport is small, I quickly got through customs, picked up my luggage, and went to get the car. However, the counter staff said I arrived early and the car wasn't ready yet. They asked if I wanted to pay extra for a larger car. I had to wait at the airport for a while before getting the car. They didn't ask if I wanted to add any extras and mentioned they would hold some money as a deposit. The entire receipt was in German, and they didn't explain it, just asked for my signature. After returning home, I realized they overcharged me 100 euros for renting a GPS. I contacted Zuzuche for help, and they patiently assisted me in communicating with Europcar. However, Europcar claimed my signature proved I was aware of the charge. Remember to check every item carefully. This was the first time I encountered such an dishonest car rental company.

When we arrived at the train station, we couldn't reach the car rental company. The Deutsche Bahn customer service didn't have any record of our reservation. We waited for 20 minutes until an employee from the rental company showed up, but he couldn't speak English. It took us over an hour to get the car, wasting a lot of time. As a result, we missed several attractions. Why would a rental company that can't speak English offer international rental services?

Communication in English was very clear. An international driver's license, local driver's license, credit card, and address and phone number were required. The process was smooth.

Downgraded the car