Security deposit for lease was not returned

Hi, my father made a lease deed for house with the house owner in the year 2011 for a period of 3 years paying 300000/- as security deposit, during the last month of our tenancy the house owner asked another 50000/- for his urgent needs and extended the lease for another 3years, totally he got 350000/- from us. while in the second term a third person approached us along with the house owner and requested us that he is going to purchase the property from the landowner, and promised us to make a new lease deed and pay the security deposit after the end of my tenure. my father is not educated and accepted it. after the sale deed was executed the new owner refused to make a lease deed with us and tried many illegal ways using goons to vacate us from the property. hence my father approached a lawyer and explained the situation and the lawer made a suit making both the old owner and new owner as defendants and optained a expart order (restraining the defendants from interfearing and evicting the plaintiff from the suit property except due process of law) after that the new owner and the old owners never approached us in any way. now we have to move to another town hence i need clarification whether any legal ways to aquire the property by law. we are ready to pay the amount for the property. from 2011 till now we are paying all the taxes regarding the property.