Unbalanced match making

Hello, i just did my placements and in every game i was the only one which was unranked last season and now, i was just against gold and platinum players, plus you should restrictionate some roles, i mean if u want to play supp , you can play only supp or tank class, because i had in every game trollpicks, teemo supp, xerath supp, malzahar supp, miss fortune supp. I just want to say this is not fair, and if u want to say ,,MMR'' is an excuse , is not because for example when i had silver 2 MMR i was against 4 platinum (season 6) players, in ranked.