Need legal advise on Builder not abiding to what was promised

Hi, I need legal advise on what kind of action can be taken on the builder if he is not abiding to the structure of the apartment which he depicted in his brochure. We have a scenario where he has depicted the entrance to the gated community on the west side in the brochure and he now is shifting it to south. When we asked why he is doing it, he says, the area on the west side belongs to GHMC and they are not allowing to construct the main gate in their place. We feel we were cheated by him by showing this gate in the area which doesn't belong to him in the brochure which was the first reference for us while buying the flat. Can you please provide legal advise on this.