Ok, I have won the national park bug contest 20 times in a row and all I ever get is a stupid sun stone, is there a way to possibly make it so that you have an increased chance of getting a thunder stone? And also the pokelathon only has a fire stone for me to buy, does it change over time or what? I have been waiting months to try and get a thunder stone and every method that I try, never works for me. Help please!!