My area in house sold by my uncle

Dear sir, we want on suggestion from your side what is to be done from our side.? we have a paternal house after the verbal distribution of house i received my portion in the house. i made a wall also as a partition. other portion of the house was sold by my uncle in which he has sold some portion of my area around 24 square feet. the party which has purchased this land, is, asking for that portion, showing map. according to the division, holding paper in my name i have but these is no map available of my area.i was dependent on the boundary which was done. since it was a verbal distribution so dispute is happening. Now how we can save my portion ?, the purchaser is saying that he will break the wall, if it is not given to him. we are living in our portion from last 4 years after my transfer to Patna. kindly suggest what exactly i have to do to save my portion though it was sold by my uncle. in selling, my uncle did the signature on sale deed. He has not informed me about this selling and not asked any signature of mine . the property was in the name of my fore father. only holding was done in ours name from Nagar nigam. My father has expired and his portion i have received during division. regards, Shailesh verma