Complex sentence: Sega went to a lot of companies to try to get brands into the game, like car companies and fashion companies, but because of the nature of the "Yakuza" game, they were rejected down by most of them.
Split into simpler sentences: Sega went to a lot of companies to try to get brands into the game, like car companies and fashion companies. But because of the nature of the Yakuza game, they were rejected down by most of them.