MMD Provica Homes possession: Agreement clauses biting now

Just got possession of my MMD Provica Homes flat last month, aur ab lag raha hai phans gaya. Builder-buyer agreement mein itne hidden clauses the, especially about maintenance and common area charges, jo pehle bataye hi nahi. Ab jab society form ho rahi hai, pata chal raha hai ki builder ne bahut saari cheezein already apne favour mein rakhi hain. My initial plan was investment for rental income, but with these extra costs, ROI ka poora calculation hil gaya hai. RERA mein complaint karna bhi seems like a long shot for these post-possession issues. Kya karein? Has anyone faced similar issues with Uttam Steels or other builders in Greater Noida? How do you deal with these unfair clauses after you've already signed?