3 years back we did an agreement with one of our relative to sell our agriculture land for 14.50L. they paid 50k and it is mentioned in the sale agreement and with in 3 months it has to be registered with the remaining amount paid other wise some interest rate he has pay. It is written in that and that document is with them. After 6 months they said they don't want to buy it. we did not return the 50K amount they paid to us. Now we got a legal notice that they paid all the 14Lakhs to us which is not true and they want the property to be registered on their name. How can we proceed in this case.