didnt got lp flex ranked

Today (2016.12.06 17:35) i won a flex game When i saw the match end its said that "starting your climb at silver v" and i played like 50 flex ranked games and i was silver 5 with 11 lp then after the game i checked my profile and i had silver 5 11 lp still and the game in my match history

Maybe i am silly and i dont know something sorry. But can i get a reason why i didn't get LP for a flex ranked win?