This occurrence was in Australia? If it were in the US I could give you lots of advice on how to determine the sponsors of a particular program.
What you might wish to do, is look into whatever reporting requirements you have in your country in regard to purchasing ads off the public airways. I have no clue as to whom you should contact. But, I strongly suspect that in your nation, there is a regulatory agency which keeps track of all ad buys. From that particular agency, you can find a list specific to programs and program times, the list should include sponsors and contact names and numbers.
Once you have that info, the next step is to find others in your local market who would be potential customers to the ad buyers and get together a petition decrying the programs content. If the sponsors sell their products only in Australia, then it does little good to get the names of complaining Americans, the sponsors will just ignore them, find complainants whom the sponsors do not wish to anger.
The best of luck to you!