Deviation from approved plan

The builder got a planning permision from chennai municipality. As per plan approval the builder constructed the flats.The building is stilt 2+22 car parking (11 Flats each 2 car parking) as per approved plan.Out of 11 flats 9 flats are sold out.while selling the 2 unsold flats the builder registered a sale deed for 368.40 sq.ft instead of 489.80 sq.ft (undivided share) and 608.40 sq.ft instead of 719 sq.ft. undivided shares. The total 232 sq.ft was less registered in those two flats. But the flats plinth area 921 sq.ft and 1352 sq,ft as per approved plan were registered in the builder's construction agreement.The ground floor was allotted fully common area for car parking only as per approved plan.Now the builder claims that 232 sq.ft.undivided share is with him in the ground floor and the builder began to constructed a commercial complex in ground floor.I thought there was some agreement between those flat purchasers and the builder. 1. is there any right to the builder to construct a commercial complex in the common area allotted for car parking? 2. The Association not yet formed, Can I have individually take legal action against the builder? 3.As i am aware of supreme court judgement, i paid Rs.1.5 lac car parking which was mentioned in the sale deed. can i get back that amount how? 4.The construction agreement was registered on Feb 2015 and the completion period was 6 months. till date i am not getting completion and possession certificates.i got a bank loan. i paid interest Rs.7.5 lac for the past one and half years. i also lived in a rented house. Can I have right to claim the loses from the builder through consumer forum? kindly i seek your kind advice. k.j.kalapa