How can I recover amount from deceased family

i am running a pvt ltd firm and through the cheques of company i had given some amount to purchase a land as advance but the middle person used that cheques for his own and the title of land had gone in his favour. after making pressure he admitted that he will return this amount back within three months but unfortunately he died . his family members told us to return this amount back after selling this property but they sold this property and had not return the amount .kindly advice in this case which legal action canbe taken against the defaulters.