Open space car parking

When we purchased two flats in Roadpali, kalamboli 410218 area (2 BHK plus 2 BHK) on the same floor and whole building is having two flats on each floor (7 storey building) at that time of purchase we received the letter from the society as one parking is covered and another is at open space. and when we shifted here they have given the random place of parking & there is no marking on stilt space as well as open space. Now we have informed all the society members in whatsapp group about that we wish to do the metal shed for our open space parking to avoid a car from wear and tear then the society secretary only is taking objection to do so and others members are not responded on that matter. (secretary is having 2nd floor - 2 flats in his daughter name, 4th floor - 2 flats with his own name, and 7th floor - 1 flat in his other family member name. that's why two members are already appointed in the committee. we have also asked about the allotment of the parking area and the marking then the secretary told us it was already discussed with your old owner and on asking of the MOM of that meeting with consent of each flat owner then we have not received any reply from there side. Please advise as the secretary is having his own monopoly and nobody is trying to oppose him.