Sale Agreement Expired

Hi Sir, There were agreement made by our family that within 4 months, buyer was ready to settle us the amount. But when he applied for a loan, he had some issues under the property, that my mother sister who left from our home before 30 years. we don't have any contact with them and not aware, where they are now. He had broken the entire house. Now he is moving into a legal via to sort this issue and he is requesting for 5 to 6 months time. He also blames us that this issue causing us to buy. But during the sale agreement, it had clearly mentioned in the sale deed that my mother sister is not responsible for this property as due to the mutual interaction with the grandmother under the court law, my grand mother had settled the amount.There were 9 people who had signed this sale agreement. My mother and his younger sister are not willing to go forward for this sale. We dont want to sell this property now, as we are getting less amount, because he is trying to spend some money to the court and he is trying to put the expense amount on our head. What needs to be done to sort out this issue?. The expiration of sale agreement happens in 2 days time. What needs to be done in order to cancel this sale agreement, as the other 7 people are happy with whatever amount they gets. But we are not happy with the proceedings. Please advice on the same. Thanks