Six Canadian companies have been penalized a total of $420,000 for making telemarketing calls to Canadians that didn't want them, the CRTC announced Tuesday.

The companies are:

Just Energy Corp. – fined $240,000.

Green Planet Home Services Inc. – $90,000.

4140800 Canada Inc. (operating as Coolheat Comfort Systems Inc.) – $36,000.

Canglow Windows and Doors Inc. – $30,000.

Budget Heating and Plumbing Services – $12,000.

Natures Carpet Cleaning (2012) Ltd. – $12,000.

The agency found that all six companies called Canadians whose numbers were registered on the national Do Not Call List, a free list founded in 2008 that allows Canadians to add their numbers if they don't want unsolicited phone calls trying to sell them something.

To date, some 13 million numbers have been registered on the list, and the CRTC has levied more than $8 million in penalties for violations.

Some of the six companies named Tuesday either didn't subscribe to the list, made calls to Canadians during restricted hours or used inaccurate versions of the list.

The CRTC said all six co-operated with their investigation.

"Today's announcement shows how complaints submitted by Canadians about allegedly illegal telemarketing calls play an important role in our investigations," said Manon Bombardier, the CRTC's chief compliance and enforcement officer.

"The information they provide help us to identify trends and more effectively target our enforcement actions. We are committed to ensuring that telemarketers follow the rules and respect the privacy of Canadians."