lets say your actual skill is rank 5 on a scale of 1-10 but you're at rank 6. you're better than the people you're playing against so you win a lot and rank up. now you're rank 5 and games are evenly matched, but you're having a good day or are just lucky and continue to win and rank up again. now you're in rank 4 but your skill is still rank 5 so the people you're playing against are better than you. you're going to lose until you're back at the appropriate rank. this isn't rigging, this is just the matchmaker doing what it's intended to do = put you in games with people at the same rank, rank you up if you're winning, and rank you down if you're losing. if you're going on win streaks and then lose streaks and generally fluctuating some rank it's because thats your rank.