Terrible because I was cheated by Interrent

They heat people. They charged my credit card unrightfully. First they charged my card without any information and when I figured out they said that the reason was "extra days". When I proofed they were wrong they gave back part of that money and said that another part of that charge is because "changing reservation". That is also not true. They didn't have car which I booked and which they had confirmed. They try to cheat me saying that it's because I picked up car 1 hour later than I had declared and information about charge for changing reservation is part of T&C. I've send they part of T&C where is information that they should hold booked car to the end of the day. I'm asking what's wrong with that company? If they try to cheat everyone clients? I demand they give me back money that they charged unrightfully but they stop answer. They said that that they gave me BB category instead of A and that's way I need to pay more. But it was because of they foult - they didn't have car A category. They also didn't tell me when I came to pick up car that they want to rented me other class. I was sure that I'm getting class which I booket da Easyrentcars. They didn't tell me that they want to charged my credit card for that change. I've booked Seat Mii 2 Doors or similar. I get Fiat 500 2 Doors. For me it was a similar car - 2 doors, 1,2 engine, small car.