winning in a row and then u r ready to lose

first time writing on a discussion, i been playing from season 2 this game and every time i play rank win 8 to 13 games and next u lose 8 to 10 games is it on purpose that riot makes match ups witch you will lose or put you in a team where there are trolls ... why is it ? you win many games in a row and promo round comes you get afks / trolls why ? once in blue moon you get good team mates in promos. i always get good team mates for first 100 ip and then suddenly in promo u win and go ahead and after one game you lose and you keep losing just why is it ? its frustrating.. :( i know the common answers you get is yeah its cuz of no proper communication / team work .. then how the fuck am i winning first 10 to 15 games and next 10 game or more i lose even with good team work and communication just explain it to me? i am addicted to this game so i cant stop playing no matter what happens. i feel like there should be a small status bar in the rank que so when you are teaming up you can see your team mates win/lose ratio like the tags which riot gives out to honorable/teamwork, so people can dodge the que and get good team mates and rank up by this people will have a little bit fear in them that yah i have to play good so good team mates will except me and play with me ranks something like that..