Purchase of land

Sir, I am resident of Tinsukia, Assam and few days ago, the owner of the land to the front of our property approached us and offered us to sell his plot to us (2295 sq. foot) Here, it is to mention that there is a transformer belonging to a private company on that property, with wall erected all around (1300 sq. foot approx) and the owner informed us that the transformer is placed there on mutual understanding between the two parties. Accordingly, he managed to obtain sell permission for the plot, where is is clearly mentioned that the property is not leased to any other party, but now the private company is raising objection on this sell and have presented a NOC ( Notary) duly signed by the owner of the land, in which it is mentioned that the a portion (700 sq. foot) of the plot can be used by the private company to install a transformer. He has also taken some money from the company. The company owner is saying that they have bought the plot from the owner. Please explain to me, what are my options? I have no issues if the transformer stays there, I need the plot mainly because to have another approach road to the main road, but I will obviously want to impose some rent fro the transformer.