I see that Barbarcle and it has so much potential beat Char... But you can't go head on shell-smashing with the sun up and Solarbeams heading your way. Teach one of your pokemon rain dance as you should've gotten it from the Aqua gang leader, lead with something to use rain dance preferably Delphox and the following turn use Light Screen. If you have a damp rock, go figure. If not, you must be smart and work with the rain. Then with the rain bring in Heliolisk (maybe use Surf?) and Barbaracle, spam Razor shell.