ICICI Home Finance has lost all valuable Property Deeds

I have taken home loan from ICICI. After registration they took the IGR copy (i.e. reciept for getting deed) from builder. The IGR is sole proof of registartion of property and that needs to be submitted to get the Conveyance deed from the Registration office. They took that saying that they will withdraw the deed and will keep in their custody as per process. However I have now come to know they don't have IGR nor the Deed. So I can't get thye property documents. Such a huge blunder and irresponsibilty from such an institution is unimaginable. Also they are not cooperating at all and denying that they have lost it.