I can understand your predicament but you need to tone down a bit and be a little mellow while posting your grievance to lawyer for legal consultation
prior to enforcement of the real estate regulation act or RERA, the stilt car park spaces were not permitted to be sold by the builders since the stilt parking came within the common areas of the society which the builder had to convey to the society while executing conveyance deed for the land and building
despite such a restriction, dishonest builders would continue to sell stilt car park spaces.
the builders are not to be blamed alone. The buyers also did not exercise any due diligence before paying money to the builders for buying stilt car park spaces
the law was very clear that stilt parking come under the common areas of the society and thus cannot be sold. Despite that if greedy buyers would buy car park spaces from builders then they have no right to cry foul later
many builders would do a separate agreement for selling car park spaces and would not mention it in the main sale deed document. These agreements would not even be registered in many cases. That itself should have arisen suspicion in the minds of the buyers. But they would just brush aside that and proceed to buy the car park in the hope that the car park space so sold to them would become their exclusive property, despite the law saying that car park spaces come under common areas of the society. Many builders would also not even accept cheques but hard cash for the car park. If that is the case, then who is to be blamed? the builder or the buyer? the builder was doing his business. It was for the buyers to exercise precaution and spend some money on getting some quality legal advise from a competent lawyer rather than paying money to the builder and complaining later!!!
the law was also made clear by the Supreme Court in its judgment of Nahalchand Laloochand. Despite the law being there on the statue book [maharashtra ownership of flats act or MOFA - check that] and despite the Apex Court clarifying the law, people continued to buy car park spaces from builder due to people's greed
the buyers then have no right to complain if they commit a stupid act when everything was so clear
in some cases the society when formed would accept the allotment of car parking made by builders [which is fine for the members who paid] and in some cases the societies would exercise their right of claiming the common areas and would not accept the builder's allotment [which would give a reason to complain by those ignorant flat buyers who without applying their mind and without seeking proper legal advice, had paid money to builders for the car parks]
then came the Real Estate Regulation Act or RERA which expressly permitted selling of stilt car parks to flat buyers and that factum is also required to be mentioned in the main sale agreement with the purchase price for car park to mentioned separately from the purchase price of the flat. The legislature introduced this because of the issues faced by several citizens due to illegal selling of car parks by builders
however RERA still restricts the builders against selling open car park spaces which continue to come within the common areas of the society which only the society can deal with. If buyers buy such open car park spaces then they have no right to complain since the law is very clear
so your grievance is completely unfounded. If you commit a mistake you cannot blame the government or the courts! Law has given you the right and the law is also very clear on the point.