Premier Elo

So season 4 I started with ~2k while being near top tab almost all games, but my friend that is almost always bottom tab (with CHEATS btw) got ~8k, so i dont understand. How is it that, i while being a decent player get only 2k elo and at most +100 per win while he being a shit player gets 8k and +450 per win???? am i just cursed or what?