i dont understand how people assume just because someone else complains that matchmaking is broken and elo hell does exist, they simply rate and categorize that poster has BAD.
it is stupid and doesnt even constitute a decent post or answer, i myself am caught in the webs of lower elo hell, i dropped from 1400 flat, to 1250 in just 3-4 days, whence i carried myself from 1100, to 1400, so that says my true rating is somehwere around 1360, altho i cant seem to climb of the 1250-1300 elo atm, and like the OP said, i almost always win my lane, assist counterjungling, secure buffs, avoid enemy from roaming, usually do everything right, when the game develops i usuually am facing atleast 1 of the enemy lanes completly fed by the jungler and lane enemy.
so yes i agree elo hell does exist, and it is very dificult to carry yourself out no matter what you do, because in the end you are rellying on the rest of your team, unless you are destroying the enemy team so hard single-handedly that they ush a surrender button at 20, but we all know that is not very frequent.
my 2 cents
TLR: elo hell exists, just because someone says it does, doesnt mean that person is bad, everyone needs to improve in way or another but it has been proven over and over elo hell does exist and MM is broken.