Issue related to registery of house

I am having ancestral house of 2storey 2000sqft + basement with 4 partners ,3 my paternal uncle + father, house was in the name of my grandfather and according to his will each four of their son was equal partner having 1000 sqft(2 from ground floor & other 2 from 1st floor)after the death of my father and due to family problems i wanted sell my portion which is 1000sqft from 1st floor on this my uncle move to court for stay and denied that grandfather having any such will but on that suit they agree that the house is 2000 sqft and each son having 1000 sqft but they don't got stay orders from court and after few months they agree to purchase more than half portion of my house i.e 800 sqft through registry and 200 sqft +my part basement remaining with me but not mention from where and forcefully they did a registry of it with my sign . now they r refusing to buy remaining portion nor giving me right to acess that remaing portion and also denying by saying your portion is only 800sqft. sir/ mam what are the legal options in front of me to solve this problem