Property Agreement

A decree was issued by the High Court of Delhi in a property matter after the mutual settlement was done between the party A and party B giving equal rights to the beneficiaries. After the decree was issued by the High court party A who was in custody of original title property papers declared that the original title papers have been lost. Consequently, the property is now fetching at a lower price. Can party B of the mutual settlement agreement who was not responsible for the safe custody of the original title papers demand the same/higher price be paid to him as property papers were lost due to the negligence of party A? Can such an agreement of sale/purchase of the property giving unequal rights to the beneficiaries be valid?