High Level players abusing new players to get S-Ranks and Mastery Points

I just finished playing a game that i got destroyed in and the the game the enemy team had a Lv30 Yasuo with the purple banner. Im new but not so new to the game im only lv14 and im sure that i should not be fighting someone at the max level. I asked him why is he lv30 and in a game with new players and he said he is playing with his friend to get S ranks and i dont find this fair at all because those keystone things hurt and i have no problem with the guy playing with his friend but we did not have max Lv player on our team to balance it out.

Oh btw i found out a few days ago that My name was a league of legends team and i keep getting called a fan boy i didnt even know about C9 i wanted to make my name SOUL but it was taken and my (ex)friend said put C9 in front of it i thought it was just a letter and number so i put C9 and now im stuck with it so i wanted to know how do i change my name?

OK thats all thank you for reading ^_^