Man not returning token moneyand didnt reveal about his remaining

My father was planning to buy a second hand commercial licensed car and got information about a car form internet. We contacted the person and went to have a look. We were eager to buy it and the guy gave us the xeroxed copy of the paper relevant for the car. He took an advance payment as a token then. We trusted the guy and he just gave us a written note on a white paper that he has received the sum as a token money from us. Afterwards when we checked all the documents thoroughly we found that the Car is already hypothecated to a bank and that its loan is still due of around 3.5 lacs. We called up the guy to ask why he didnt mention about the hypothecation and remaining loan amount during our visit but he didnt say anything and also said that he will not return the token amount. We asked him to clear his part of the loan and after getting NOC for the car we will buy it. He didnt do that. Now he is not picking up any of our calls. I know I dont have ay proof that we have paid him any token amount except the white paper but is there any legal way that we can take. Will lodging an FIR help? Your suggestion is highly appreciated.