Owner not getting the property registered under my title

Respected members, In november 2016 my father entered into agreement for the purchase of the property(residential building) of Rs. 53 lacs, and as per agreement the date fixed for registry was in January but at that time due to demonetization the whole setup got delayed and both the parties mutually agreed to get the property registered in month of march.Amount of 13 lacs was paid at the time if agreement.We requested for the possession of the property as we wanted to get the renovation work done and owner agreed to the same. after that we paid them 20 lacs more in 3 installments and also spend 27-28 lacs on renovation and finishing work. as the registry date arrived we approached owner for registry but he said to wait for some more time as he said he was busy in some work and will not be able to get the registry done. since that, today the time has came he has not transferred the title yet and now we came to know that the owner don't have the registry with him and the same is deposited with bank as collateral security against the loan taken by him,What remedies are available in this case please suggest.