if bank misplaced the conveyance deed against which they have given the home loan, then what shuld I Do?

I have taken home loan from one bank and now i want to foreclose that loan and transfer the balance to an other bank but previous bank say that he has misplaced my conveyance deed against which he given me the said loan.
1- Then what can I do with that bank.
2- How can I retrieve my conveyance deed as original.
This happened in India So Pls. reply according the Law of India.

To sell the house and close a housing loan?

Do we need to tell the bank that how much we are selling the house? Since the Bank will have the original document, will the people from bank will ask about the selling price also or it is just pay the remaining loan amount and close.