Abusing the tourist

It seems to me that Thai Rent A Car takes advantage of the tourist, they charged us a fine of 5,000 baht because the boy who checked the vehicle in the delivery assured that he had smoked inside the car, the revision was done when it was still dark and had not left the sun and affirmed that there were some particles in the floor of the interior of the vehicle that showed that he had smoked inside. Although we denied having smoked inside, the boy told us that if they had smoked and that they did not return the bail that "was" 5,000 baht in a clear position of power since they had bail. We told him that we wanted to make a claim because we were not satisfied with his accusation and fine, but the boy told us that the claims could not be made until after the time of our departure from the flight, so we could not claim, we told him we wanted to warn the police and the same case, it would not arrive before our departure from the flight. I think they are abusing the tourist and this in the long term will harm them because at least we will not return.