Attention: Stop renting from this car rental company immediately! Here's what happened to me at Zagr

Attention: Stop renting from this car rental company immediately!
Here's what happened to me at Zagreb Airport in Croatia. Despite asking three times and confirming that I didn't need any insurance or additional fees, the rental company still secretly added insurance. The rental itself cost 2000 (including the super collision damage waiver recommended by ZuZuChe), but they added an extra 4000 in fees. To prevent me from noticing, they deliberately didn't show me the full contract and made me sign using an electronic device while folding the page showing the fees.
Their malicious intent and despicable practices are outrageous and disgusting. I can't imagine or understand how such things could happen, especially with AVIS being an international rental company. This clearly reflects that their employee training is all about treating customers as cash machines and taking advantage of them whenever possible (they even gave me a car with less fuel, and I refilled it generously). Given this company's values, who knows how they would treat you if there's a problem with the car or if it breaks down on the road? Do not rent from them!