Chapions blitz how is placement made

I currently played the blitz as i did last weekend and Im so frustrated   how is the league chosen?   just play in diamond league with unit levels 10 plus yet currently i am in platnium 3 with gdi and gold 1 with nod.    first four games losses and then ended with 7 losses and 3 wins. this is totally not fun you can say its supposed to be tuff and a challenge but this is just not even fun. Yea i got to platnium with GDI because a few games people did dumb * so now i can lose and lose atleast i will never go past platnium 3 but again match making is ridiculous.  You can also say to be fair it needs to be at 50% win and losses I'm at 45% GDI and 43% NOD maybe this is alright but how to ever progress if not above 50%.