Title clearance

Buying a resale property where the property has been in the same family, but .. 1) seller’s father had bought this property from the builder back in 1988 under the name of a private company 2) in 1992 the share certificates were issued directly in father’s and mother’s name 3) both have passed away since and now daughter has transferred the flat on her her name, and the share certificate is also on her name The issue is that agreement between the builder and the private limited company exists, but no document was ever created for transferring the property from private limited to the 2 individuals. My bank from whom I am taking a loan is calling the Titles to be unclear questioning on what basis did the share certificate got transferrd to mother and father without any resolution being passed in the society or any agreement between private limited and individuals Therefore, I can’t even follow the process to dig out the document from sub registrar since no agreement was ever made Is there a way to still pursue this property, and in that case what are the alternative documents to be arranged from the seller . Or should I let it go thinking something is wrong here?