How to deal with spam calls ?

Probably a relevant question for many in TO, hence posting in askto.

I've been badgered by calls from 'service Canada', 'rogers' and 'canada post', which turn out to be scammers sitting in India or elsewhere. These calls are annoying, not believable in the least, and have remarkable tenacity (they call back incessantly).

Is there any place to report these calls, so the authorities can take action ?