Not getting land conveyance from builder

Deemed conveyance is not valid as much as conveyance deed.  The reason being is the conveyance deed is made by the builder after his yes and the builder pays the stamp duty and registration fees on the transfer of land and building through conveyance deed.  In the contrast, deemed conveyance are not approved by assembly of Maharashtra.  It has just been done notification.  Further flat owners do not have capacity to pay huge stamp duty on deemed conveyance and the same can be challenged by the builder in the high court.