Agreed Amenities not finished and Improper Parking Lots allotted by Builder-Bangalore

First of all I thank all the Advocates here for supporting the Flat purchasers in a legal way. I have few points to ask on Stilt parking allotment method in my Apartment. All details are given below for easy understanding. This Apartment is in Bangalore with 60 Flats and approved by RERA and it’s a JV between Land seller and Builder. This project has already received the Occupancy Certificate in the month of Feb-2021 by BBMP.As it is a new apartment the purchasers have taken procession in a timely way(Few have taken the procession around 2 years before)and as of now around 45 Flats are occupied and aprx 08 Flats are unsold, Few are under Interior work. As all the residents were continuously following it for all pending amenities like Party hall,STP,BWSSB Water, Fire Alarms, Backup Power, Swimming pool, Badminton Court, Children Play area……etc. are not yet completed despite many follow up’s and flat owner's visit to Builder residence. The commitments given by builder have failed many times and all are upset as the mentioned amentias are still unfinished. A new development has happened around a week back and the builder has sent the parking allotment letters to all occupied flat owners through somebody. The Builder was not present to give the allotment letters and now he is not taking calls from Building residents. The real problem is the Parking places allotted is not in order and few of the parking places are unscientifically alloted.Few are in semi covered areas and open to Sunlight and rain. Builder has allotted all these parking slots as per his will and wish and in a random way. There is no basis/logic in the allotment process and few are having trouble in small parking or improper parking. It is also found that 2-3 extra parking's are sold to few Flat owners and a big area is allocated as one parking where 2 Cars can be parked comfortably. Like this there are many irregularities found in the parking allotment. We have sent a letter to Builder and tried to call builder but there is no response from his side. Kindly suggest how we can go about these issues as the builder is not bothered to fulfill the committed amenities and allotted faulty Parking lots.