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.