Legal rights of a wife who got release deed

Hi, My father and his first wife had a release deed agreement 10 years ago and as a settlement some land was given to her. 5 years ago my father expired with a will saying all his incomes like pension and death benefits from his organisation(he was central government employee) should be given his 2ND wife who is my mother and his son( me brother). All these 5 yrs his first wife has been contesting for the death benefits and pension. Now the judgement came like they(his first wife and her daughter) are only the legal heirs but instructed the organization to sanction the grant as per the will because the will is proved true and last one of my father... but the organization is denying for granting the pension saying they can only grant pension to the legal heir and not to us. Is there a release deed can take an effect in this position ? Also it is not an registered deed. What is her rights in the pension. My father was with us for more than 25 yrs and they never appeared... Now only for money they are disputing . Please advise us the further steps..