How could i vacate the sub-let tanents from my shops?

Dear Sir, My name is Mohinish Patel. My brother and I have 2 shops in Anand, Gujarat. These shops were given on rent by my grand father to a person, who is deceased in 2007. Before his death, he conveyed to his family that he has promised to give back these 2 shops to the owner. At that time, my father was looking after these properties. But, instead of returning, his son, who is an American citizen, gave these shops to 2 persons by accepting Rs. 500,000.00 each from them. He is also collecting rents from them. His mother convinced my father to pay rent Rs.1,000.00 and he collects more than Rs.18,00.00. Both son and mother are USA citizens and lives in USA. This November, after my many persuation he agreed to pay Rs 20,000.00 for each shops. But, he never paid me. My query is how shall I vacate those sub let tanents from my properties? Please guide me and oblige. Many thanks, Mohinish Patel