Lost share certificates

Hi

Im new to this forum

My great grandfather held lot of shares of walchand nagar . It was alloted in the 1960s.
Problem is i dont hv any share certificates or how much quantity he held
He was the legal advisor to Walchandnagar and he was alloted some shares.
Also all the dividend reciepts also is not available and my grandmother didnt safekeep them.

So i hv no proof about folio number or any dividend reciepts.

What can i do?