Rank Flex

Okay I am so confused with this whole Rank Flex system and I am actually not happy the result that i am placed in my solo/duo rank so Beginning of S7 I was playing Ranked Solo/Duo Games for whole Ten Games. So when i was done with the Ten Games i ended up in BRONZE 5 with 0 LP even tho i won SEVEN RANKED GAMES and lost THREE GAMES and i would like to know why was I placed BRONZE 5 with 0 LP when i won 7 FLEX Games and lost 3 Games