Parking Space Disputes

I have bought a 2BHK flat having 2BHKs in the front side and 1 BHKs in the backside in Uttam Nagar Are. Its not an apartment but a builder made buildinga which is owned by 9 different families (4-2BHK & 5-1BHK). All the owners of 2BHK except the roof floor have been given a common car parking where car size should be equivalent to small hatchbacks and 1BHK flatmates have been given only a common bike parking. Now, the parking area is having a baccha flat and due to which it is impossible to park 3 small hatchback cars in that and that is the reason noone is using the parking for car to avoid any dispute. The below are my questions. 1. The 1BHK peoples have reserved their parking space by putting stickers on the walls of the parking. Is that legal, since its a common parking space? 2. To avoid dispute I am not parking my car in the parking instead of that I have a scooty that I am keeping in the parking and there is spare wooden door that I have kept in parking that hardly consumes any space. The 1BHK persons are asking me to remove that wooden door from their even though there is no issues with that and they are parking their allocated bikes. Can’t I keep my small belonging in my parking space? 3. They are quite often demanding money for various maintenances which we are not agreed to do and we have not signed any agreement with builder or anyone that we will be paying any maintenance. Can they force us to pay any maintenance which we don’t agree for? 4. We have covered our balcony with a steel roof which they are asking us to remove since they are finding difficulties to move their huge furnitures through balcony. They often threatens us to remove that dust roof. What can be done for this?