Oral Gift Muslim personal law

Hi All, We are in possession of a property for the past 14 years and running a business on it. My uncle( fathers younger brother) had bought this property and registered it under his name. He then made an oral gift under Muslim personal law to my father after receiving an X amount of money, this was done 30 years ago and my father still has those transaction amount bills with him that he had sent through a money exchange to his bank account which clearly mentions his name and account number,however it doesnot say for land transaction. My uncle passed away in an accident and none knew of this setting.However we never got it registered until this year because my uncle's heirs still think they are the legal heirs. Property taxes from date of purchase of property till date are on my uncles name and also the electricity bill. Now that we registered the property on our name we are changing the names on the electricity and property tax. We have a Partition deed, Settlement deed and a lease deed registered in my father's name to us by linking the previous document that he registered under his name and this has been done keeping in mind Muslim Personal Law Oral Gift Hiba. I would like to know in the court of law how strong is this case in our favour and what needs to be done to build a strong case in our favor. And also we have been enjoying possession for 14 years now because we were living outside the country previously.Please advise. Thanks heirs think they still own the property. Since we were living outside the country