Query regarding registry of the property

My father had purchased a plot he had paid all the money to the seller at that time the society told him that the registry will be done by them few years back they told that they can't do it because it is already been done once so when my father consulted the seller's family they told us that the seller is dead so we asked the society by whom should we get the registry done so the society gave us the name of the heir who's name was their in the society records the owner had her name changed with her heir's in the society so we contacted the heir and done the registry of the plot with her but we mentioned about all her descendants in the registry including one with whom we had the registry done now we are told that we need the death certificates of heirs who are dead and no objection by others but now we have found a document in support of the person(heir) who had done the registry that she was made the owner of the plot by the seller and had her name registered in the society so please tell me what documents do we need in support of the registry now or other measures that we can take.