Parking Allotment by Builder

Our scheme has 2 Towers of 1 BHK and 8 Towers of 2 BHK. In sale deed of 1 BHK its written that sufficient parking will be provided where as in sale deed of 2 BHK, it is written that Parking slot will be alloted. At the time purchasing flat builder did not tell us that they will construct garden on first floor and allot parking in ground floor. In our case half of the area below our tower is consumed by shops developed by builder. We are asking builder to allot equivalent area consumed by shops as a parking. My questions are 1) Do builder have right to allot parking? as whatever land on which scheme was developed is common for all residents. How builder can allot piece is land to park to one member? 2) Its is written in sale deed about allotted parking means builder sold parking? or he has right to write such things? 3) Do builder can build first floor garden and allot parking in ground floor? 4) Should we get 15.0% FSI of our tower as a parking space or builder can allot to other by decreasing our space?