Inheritance Of Maternal Ancestral Property

My maternal grandfather inherited a house, land and shop from his father. My grandfather had 2 sons and 2 daughters. My grandfather did not buy the property but was gifted it by his father. My grandfather denied property rights to my mother, as she is a married daughter. My mother died in 2016. My grandfather has registered a will in 2018 gifting the house and shop to his sons and a minimal amount(7.5 lakhs ) to each daughter(To me and my brother, as my mother predeceased my grandfather). My grandfather has died in 2021. My uncles now claim that me and my brother, as legal heirs of my mother, have no property rights over our great grandfather's property. They have not included me and my brother in the legal heir certificate as well. Is this true. If not, what are the ways to get legal respite.