Drivalia Italia - unauthorized billing

On 15.11.2025 I rented a car in Naples. The lady at the office at the airport had us sign contracts. Unfortunately, they also contained information about the car that was not shown to us. Then we were sent to pick up the car at the parking lot with the keys. No employee handed over the car here. He didn't even get up from his chair and said let's go.
This is a completely different approach from other rental companies that always go through the car and show it. We saw that there was only a tire repair kit in the trunk. We didn't find it strange. Nowadays it is quite common to not have a spare tire, but only a repair kit.
Plus, the car was a hybrid, so it was completely logical because of the battery. That's why we didn't take a picture of this. It just seemed normal to us.

We had an unpleasant surprise when we returned the car in Rome, where we were told that we had taken the spare wheel and were charged €300. I immediately contacted Drivalia by email. Unfortunately, I have not received a response yet. I only received an invoice for the spare wheel.

I feel really cheated. The documents for the car were processed in the office at the airport; so even the lady in the office did not physically see the car. We were not informed about the equipment of the car. We were only given a contract to sign without any explanation.
As a standard, the equipment and damage are checked and signed for at the parking lot when the car is handed over. Which we expected, but this was not the case here.
I have to say that I feel damaged and cheated. I don't want to pay for something that is not true and was not in the car.
How can I defend myself? This is terrible behavior. Non-standard from the beginning. It gives me the impression that it is targeted. Thank you