What really happens after booking a flat in Bengaluru?

Since January, I've been shortlisting 2BHK flats in Bengaluru, mostly around Whitefield and Sarjapur Road. My budget is around ₹95L-₹1.1Cr, and honestly, it's my first property, so I'm super nervous. I've visited projects by Prestige, Sobha, and Brigade. Sab achhe lagte hain on paper. But I'm really worried about what happens *after* booking. Log bolte hain customer support gaayab ho jaata hai. Is it true for these big names? Do they actually communicate during construction delays, ya ekdum silent ho jaate hain? Also, possession ke time pe koi hidden charges, like unexpected PLC ya maintenance deposits, aate hain kya? I want to avoid last-minute shocks. Please share your experiences, especially about their post-booking journey!