Transfer of property

Hey, my mum has got a land from her father and her sister and her husband weren't allowing her to sell the property, they said that they have given some gold and done my mother's marriage. At first they weren't ready to give the property only, later however court has given equal share of land and now they are stoping them later with the help of police land has been sold with consent that , the part of land of my mum will be left to them without any money, to the god naag and they won't make any problem while selling the land. Because there is a naaga bana and my mum's brother in law is a priest there. So my mom agreed. Later land was sold, now they are calling everyday Asking us to immediately transfer that land into their name otherwise we are supposed to give INR 50000 to them. My mum has asked 3 months of time still they are threatening us.. we Said we want to transfer the land according to the conversation but we are kinda busy .. but they are not agreeing instead they said that they will sue us and cursing us.. we got the part of property paper of remaining site.. now inorder to transfer that land to them what we have to do sir?