Companies only understand one thing: Money.

You may have seen the petition:
https://www.change.org/petitions/tell-village-voice-media-to-stop-child-sex-trafficking-on-backpage-com

Village Voice Media may hate the publicity, but they'd hate advertisers pulling out even more. Unless we demonstrate to the advertisers that we see their advertising with a company profiting from sex trading as reason enough to stop doing business with them, they will continue to due business with those that profit from sex trafficking.

Sign this, but more importantly, refuse to do business with them as long as they financially support sex trafficking profiteers.