My Ranked Flex And Riot Cheesed me and is messed up

I won 8 straight games against diamond players and couple master people in my ranked flex queue. I then lost 2 games afterwards and got placed into plat 3. Ok I'm happy with that. I am plat 5 in Solo Queue. It then tells me I need to play another placement game today inorder to get my placing. Wow OK so u took away my damn plat 3 and make me play another. I played and Won another game and got placed Gold 5. Wtf I didn't even lose i won my game and I got placed lower. You can't just give me a damn position and then take it back and give me lower. I played hard against those high diamond players and had a positive KDA. Riot you need to fix your system. This kind of stuff honestly is tiring because its happened in the past and makes me want to just rage sometimes.

I hope you are reading this RIOT Employers and fix this issue. You can't just give me plat then have me win another and give me gold 5 8 ranks lower. Please write comments and make sure that this notice gets announced.