Stilt in privately buid flats

I own a second floor flat in Delhi. The owner of the land had free hold right on the land and built four flats in it. We purchased the flat at a time when only the structure of the flat was erected. We were given a copy of the structure that has a stilt parking without any other permanent structure. However, a room and a toilet in the stilt existed during construction. These were used by contract builder for keeping the material and for the labor. On completion the owner did not remove these structure and started using it for other activities. Later, the owner died and his 3 siblings took one floor each. They gave the room in the stilt to a poor family of 5 members without our consent. They did not pay any attention to our verbal disapproval of this act and always tell that the family is kept for the security of the stilt area. The family staying in stilt also works as servant in their flats. Since the room in the stilt is small, the servants sleep in the parking area and quarrel with us if we park the vehicle in any way that obstructs their free use of it. As per the agreement I have right to park two cars and proportionate undivided rights of the land underneath. I had put up an online complaint to the MCD which took no action for the last one year. What are the options available with me to get rid of this family staying in the stilt area. Can the illegal (as per plan approved by MCD) structure be removed to end the trouble we face in the parking area. How should I proceed in the matter. Please guide.