Moved into Noida Extension, got hit with a bill.

Honestly, I'm still fuming about this. Just got possession of my 3BHK in Sector 150 a couple months back. The builder's brochure showed a clear price for the flat, but the final all-in cost was way higher. Things like electricity connection charges, RWA corpus fund, and even some obscure development fees just popped up at the very end. It added almost ₹10-12L to my initial budget of ₹95L. Did anyone else face these hidden charges at possession in Noida Extension? What did you do to manage it?