RERA complaints: Do they actually work for possession delays?

₹1.5 crore for a 3BHK in Sector 150 – I'm eyeing Marshal Green View, but builder delays worry me. I know RERA exists, but how effective are RERA complaints in Greater Noida? What are the actual legal options if builders, say Elite Group, default on possession? Can buyers really get compensation or is it just a long wait?