Encroachment in our Agriculture land-a strange case.

Dear Sir/Madam, I need some guidance in my above mentioned subject. In 1967 my Grandfather had purchased agriculture land by paying Rs.1300 and got possession of it, but after two months the party who sold his land, along with his villagers prevented my grandpa and father to enter in the property by muscle power and when my grandpa went to meet them for refund payment, they denied and demanded some more money to complete agreement.Hence Rs.700 more payment was offered by my Grandpa for completion of agreement . (I listen this story from my father he was 15 years old at that time). So, again he went to took possession of land but at that time their family members again prevented him to enter into property and had injured him. They threatened him that if he will come again, they will kill him. My grandpa was badly shocked as he had invested his whole saving in that land and people advised them to forget the matter and to do some else business because at that time my family had only two members my Grandpa and my father (my father have no brother and sis) also they have no money and support for court case etc. After some years my father got married and i was born in 1976. I was not informed about the documents regarding the land which my grandpa made with that party at that time.I was in the belief that we had no legal proof about ownership of land which my grandpa possessed. Now i am 38 years old now and have a grace of god in 360 degree. Recently digital survey of all land was carried out by government during it , i came to know that the old disputed land is on the name of my grandpa. I took that survey no. and got 7/12 utara and 8A and all other entries , i was surprised that the documents were in the name of my grandpa.So i asked my father about copy of agreement , he was not sure about it, so we searched for it.I got that original agreement . Also the entries in talati office matched with it. My grandpa passed away in 1998 .I applied for entry of my father's name in 7/12 utara three months before and today my father's name has been updated in the all relevant documents of that land. Due to fear, lack of money and proper guidance, many years passed away . During this period some 3rd party has built its homes on that agricultural land (Land without N.A). I request to guide me to solve above mentioned dispute at earliest. Thanks and regards Anil Patel M-9427335035