Matchmaking Needs to be Examined

I would like to start this discussion by stating that I am a player willing to learn and adapt.......I've been playing the game for the past 5mths and I'm disgusted by the matchmaking process which Riot has implemented. I cant understand why riot would allow someone who plays just above average in most games, who focuses objectives to fall from s3 to s5 within 24hrs. The hypothesis I came up with for such an ordeal is that they may be some biases towards players who spend more money on the game as for others. I have a friend who plays the game as well and this is not meant to be taken in a disrespectful way but I'm clearly a class or 2 above him, however riot sees it fit to give this individual s1 and to give me s3. I couldn't comprehend why at first but I comforted myself by saying well he won more promos than me (idk how) but I didn't argue about it. Later I played ranked and won 4 in a row got me 86lp. I was happy and ready to climb the elo ladder then I lost 5. I dropped to s4 I was sad but I didn't play as well as I'm used to so I didn't complain. I ranked back to s3 and got to 79lp. I lost 6 this time and went to s4. I didn't complain still and that's when everything changed. I lost probably close to 8 and dropped to s5. I've had enough of the injustice because in the matches I've lost I either carried or pushed objectives yet my team mates kept feeding, going afk or being toxic. I'm not going to lie I myself was toxic but after doing some research I've discovered that being toxic does not help so instead I encourage or stay silent. My unskilled friend buys a lot of skins and all my friends who are less skilled than me who spends a lot on skins get good match ups and when they lose its no more than 2 in a row. Why does the match making benefit the rich (spenders) more than the poor (conservatives).????