Property Dispute with distant relative

Hi Experts, We have a joint property where my father and two uncles used to live together. History of Property: After partition when my grandparents came to India, my grandmother bought a house from his elder brother(She had 3 brothers) in 1972 and the irony was she never got the papers transferred but in good faith just gave money and started living and till date the house is in our custody and one of my uncle is staying there. My grand mother's brother had created a will to give that house to his younger brother's son as he had disowned his son as per his will. So basically my grand mother's younger brother's son's have got this house transferred in there name in 2008 I lost my grandmother in 2011, and his elder brother had died in 2005. Issue: Now my grand mother's younger brother's son's have sent notice to my uncle who is staying there to vacate the house. Please let me know what route can we follow and is there any way of hope for us. Thanks Waiting for your Advice !!