when someone who feeds says they are smurfing

good job adding me on your elo boosted or buddys account. Alot of people try to say that to me because im not a polite diamond player ill tell you how bad you are and shit like that if you are a douche. This kid however has 200 games played and goes 2-7 claiming to be platinum 2? against silver 2's? LOL. me and my buddy were actually smurfing im diamond hes plat 4. We single handedly destroyed our lane while him top and jungle fed. Easy way to tell if someone was boosted, key bindings, item hotkeys, amount of games played, quality of games played. Im going like 20-2 as a score every game i play solo , he's going 0-1-0 7-15 then tries to add me on a buddys account LOL. How nerd can players get?