Agreement not provided by house owner..he passed away..

I took a commercial place for rent for 12000 per month with 1 lakh fifty thousand rupee as advance in 15th Nov 2018. And The owner agree to give agreement but due to his bad health condition he was not able to give agreement..finally jan 14 he passed away ..after that I asked his son to give agreement who is staying in same building..I paid Jan rent to the son..after a week his mother and sister called me saying that dont give rent to is in my (mothers) name..I said OK but take a responsibility of my agreement...but both son and mother are not ready to agreement.. .they are fighting only for rent..son filed a attempt murder case against mother and sister.he filed FIR..he is telling WILL is under my name..but he didn't show the will to me..orally he said I will give back your advance money but I cannot give agreement. ..because I filed it is in court...kindly suggest me who is the correct person to get whom i have to give my rent..they said property is under mothers name..WILL is given by Father to the mother left the house..if she give a complaint or if she take any legal action against son like injection order... then how can I get my advance amoun. .pl give a solution