Objection for Mutation

Hi Sir/Madam, In Dec 2015 my father has purchased a property(House) from Mr.Narayan, who has one son and 3 daughters. All are married & got settled. During registration process , we have taken witness signature from his son. We applied for mutation(change of name) in concerned municipality with registration documents enclosed. Later we came to know that there was an written objection in municipality raised by one of the daughters(Ms.Renuka) of Mr.Narayan, that she also has the share in the property and no mutation should be happened on that. This information is not aware to us and we proceeded for purchase by checking the EC. Objection was raised before we purchased the property. Now municipality official's are saying, they cant do the mutation until we get a NOC from the Ms.Renuka. We strongly believe that they trying to trap us for money. Mr.Narayan has raised his hand and not responding. And they are demanding for huge money for giving NOC. When we have a registered documents with us, why municipality officials are giving priority to the objection raised by Ms.Renuka that too which is been raised prior to our purchase. SO the Registration document doesn't have any value here? In what way they are linking with mutation objection & Registration. Will there be any cut off time for any objection raised by an individual? Please help us out how to resolve the issue. My father is under very depression as he spent all his service amount for the house purchase. Thanks, Shaam