Giftdeed

My father got property from his father which he demolished and constructed four house on it with his money. We bleong to christian family. My father has four sons. Im the elder son. My father has gift deed registered one house on my name, one house on my son name, one house on my 3rd younger brother and the last last house on my 4th younger brother. My 2nd younger brother has passed away so he was not given any house. Now my dad also has passed away but before death he had gift deed registered all the houses mentioned above. Now my 2nd brother has two daughters and they are claiming share in the house that was gift deeded to me. Where my gift deed states that my wrote as from this me are my other sons and their heirs has no rights on this proeprty and registered to me. So my 2nd younger brother daughters have become major and sent me leagal notice claiming the property that was gift deeded to me. Kindly advise on this issue.