land property in the name of my brother, what is my share.?

There is land property purchased by my father who is no more. The property is purchased on my elder brothers name, but during partition it was agreed by all that both will be getting the equal share. But now he is claiming the whole property. I dont have any proof except one informal document which was made during the partition which contains all the partition of property and it is signed by my brother and me as well. I have the carbon copy and original still is with my brother. So any possibility that I can get my share or stop the sale or any construction on that land by court order.