Supposedly bought a taxi with an e-stamp agreement, how to return?

Hello, My father is a very naive and humble person. One day, a poor cunning guy (Azhar khan) who used to mend the computers at my father's office lost his job. So he asked my father to buy a taxi to earn his living through ola/ uber and rest payback him. He somehow agreed to him after his lot of pleading. Next day, he brought a guy with him, a taxi seller (friend of Azhar), and they did an agreement at a notary. My father paid the advance amount of Rs 1,30,000 and they beguiled him to pay subsequent loan EMIs to the taxi seller. No NOC, No loan transfer, No transfer of papers have been done. We came to know this poor cunning guy (Azhar) is a fraud guy. He has taken a lot of money from different people and has taken 3 lakhs (2lakh loan taken by my father for him) from my father apart from the taxi. Now its been more than 40 days, that taxi is with us. So, how much valid is e-stamp paper or is there any possibility to get our money back from taxi seller. What to do?