When you see him use Billow, wait a little while before transporting away because he cannot cancel the ability and transporting away too early gives him time to close the gap on you.
Movement is key! use your dashes to move around him. If you're running low, Reflect so he'll stop shooting. it'll take a little for his gun to start back up, capitalize on that time. When ruckus ults, just deflect it. he usually wont stop.