My Father Is Neglecting Me Because He Said That Im Not His Son

My family consists of 5 member father mother, 1yelder married sister and 1younger unmarried sister.in this I'm boy of 28year old unmarried.untill my 23age all are happy but onwards there is a dispute and misunderstanding between my father with me.there onwards he tells I'm not his son.and he also told I'm not any right over his property i.e 40 acres agriculture land.but my mother and 2sister are ok with me . only father squarling with me .how I can solve this problem.how I can prove lm son of him.my mother told but he is not agreed in this situation.how I can take right over my father property