Well, it was mentioned nowhere that they never beat him. It was only ever mentioned he clashed with Roger and Garp. So he fought them at one point in his life, and no one knows when it happened. The only thing we know is that he stopped being a pirate 30 years ago after his duel with Garp, so his fighting with Roger must've happened even before that. We also know the dude was worth around 550 million in his days of glory while Roger's bounty exceeds his bounty by 5 freaking billion. The fact that you're sitting here suggesting Chinjao was anywhere remotely close to Roger is mindboggling to me.