Builder has not given me Occupancey certificate from BBMP Bangalore, what should be my next step ?

My builder provided me with the ”commencement Certificate’ of BBMP,Bangalore but not \’Occupancy Certificate, though the project completed some times back. So:

1. Is it not mandatory to obtain O.C. from BBMP once you have collected CC?

2.In case builder failed to provide OC what can be the problem in future ?

Ranjan