Buying a property of a Deceased Owner-Succession Certificate

I had paid a token amount of Rs 5 lakhs to seller of a property. Seller passed away intestate (without a will) before executing registration of agreement for sale. Seller's wife had already passed away two years back. Now the property is ownerless. Seller has two daughters - one Indian resident and other NRI. NRI daughter is ready to register a release deed on favour of her sister to let go her share in the property through inheritance. Society is ready to transfer share certificate in name of one of the sisters who is the Indian resident on basis of 1) registered release deed 2) affidavit 3) indemnity bond and 4) death certificate of father. Can I execute and register an agreement for sale with the Indian resident daughter without succession certificate. Issue is Succession Certificate would take 7 to 8 months of time to receive from court. Seller is not willing to wait till that time. We, buyers also can't wait for 8 months. Should we ask back token amount? Or is there an alternative?