Gurgaon brokers: Kaise deal karein with hidden costs?

Brokers ka commission structure kaise negotiate karte ho log? Just moved into Adani M2k in Sector 66, aur lagta hai broker ne kaafi batein chupaayi. They said final price is X, but ab maintenance, OC, aur even parking ke liye extra paisa maang rahe hain. Negotiation ke time they promised all-inclusive but ab yeh hidden charges nikal rahe hain. Mera toh 1.8 Cr ka budget 2 Cr touch kar gaya. Kaise trust kare brokers ko? Kya koi legal way hai inko accountable karne ka? Please share your experiences.