If it's been that long, just playing something else. Premades are forced on you in every game mode now, ranked is not a sanctuary. It doesn't exist any more. Premades are horrible cancerous vile vermin that need to contract human immunodeficiency.
I suggest dota 2 if you want not to deal with premades, and want a better game. and one more balanced. There is also smite, for a third-person perspective and another third-person perspective game like this is paragon but it has no match-making atm and also has premade issues at a point not long into playing. In my case, and some others from what i saw on reddit. You win hard and way too many times and then hit rock bottom once every othe rgame is a curbsotmping premade, which is the reason i left this on this season. At least i won't be putting money into paragon though, even if/when a solo or duo queue only queue does come out along with elo. Paragon has promise though, and if you're gonna get curbsotmped by little smurfette premades, it may as well be in paragon over this pos. i suggest dota 2 though, but smite is also fun i did it in closed beta and once in a while after ob or release for a while.
TLDR= league is imbalanced, beyond repair, and isn't fun any more. Play Dota 2, Smite, or hold out hope for Paragon and give it a try in open beta currently. Also, 'solo' is the role most shit on in this game currently.