i presume agreement for sale is not registered
2) if agreement for sale is registered then deed of cancellation can be executed by consent of parties
3) since agreement is expiring on 31st December 2016 the seller can by letter inform you of cancellation of agreement and refund advance paid by you
4) if seller fails to pay inform the seller that since title is not clear and marketable no loan was sanctioned and to refund your advance money paid
5) if seller fails to pay file summary suit for recovery of your money with interest