Cancil agreement of sale deed

My grandfather had singned an agreement of sale of land on 19 Nov 1988 and advanced given at the time of agreement which was registered. But all the legal representative of grandfather did not signed except one.all representative were adult at thai time. conditions of this deed is if vendor will fail taking signature of all legal representative then vendee has right to demand his advanced rupee. vandee shall be purchase land within 4 months from date of agreement. if the vendor fails to sell land within said period then he have right to sue under specif relief act. But the vendor fails to take signature of his legal representative on deed nor vandee try to purchase land. vendor didnt apply for cancil deed. But In the year 2003 vandee file a suit and claim for register the land in his favour. we didnt recived any notice an in 2005 pass exparty order in favour of buyer or vandee.then we present in this case from 2005. My adv file for WS and application for restitute or revoke this order under CPC. now present this case on judge table. please advice me