Bestech Group — covered area less than what was promised

We booked an office in bestech business towers mohali and it was conveyed that the super to covered area loading is 35% and super are is 1096 sqft. When we measures the area onsite the loading is coming more than 42% and informed the sales representative (Mohit goel & manpreet) to do the corrections in the bba and do the necessary adjustments in the price. We are asking them to get the measurement done themselves and share the loadings done but they are not willing to listen and now saying we sell on super area and it's upto company to decide the super area. Mohit said we can quote anything on super area and sell the same area mentioning 1500 sqft as well and least bothered what customer gets as covered /carpet area. This is the clear case of cheating which bestech representatives are doing with their customers and maligning the bestech image. We have put multiple emails to mohit & manpreet and calling them on regular basis to correct the area in bba and adjust the price accordingly but they are taking no action on the same. Look forward for the resolution