Matchmaking is broken.. again

So i played a game with my friend in flex queue, i myself haven't played much ranked this season. Im currently gold 5 and my Friend plat 5. We went into the game seemed reasonable on our side gold 5, plat 5, plat 2, plat 5, plat 3. All good and then i look at the enemies side.. plat 5, dia 1, dia 5, dia 5, plat 5. How is that fair at any rate? Like me and my friend somehow won our laning phase against the dia 1 but the rest of the team didn't do so good. Not that i blame them since most of them were completely out matched. So yeah that's pretty much it. we lost the game 40 V 22 i don't know how to end this over than saying "Fix it Riot" thanks. I would like to hear if this is a common thing and if it has happened to any of you people.

Ps: Sorry for my bad grammar working on it! : P