Illegal Hunters — Illegal construction

Address:

New Delhi, Delhi, 110048

I want to complaint regarding the illegale construction in our building (N-9 Greater Kailash-1 new delhi-110048).
We gave the complaints twice in MCD office personally. but no action had taken so far.
The person who is constructed illegally he is a CBI officer and threating all the residentials with his son.
According to us the JE AND AE (MCD OFFICERS) are also with them.
plz help us wat to do now and how to stop this illegal work