Ranked System unfair (AFK Teammates too often)

I haven't played LoL since season 3 and now that I am back playing, I was placed in Gold 5. However since the start I constantly lose double the points than I win. It is impossible for me to get promoted. I even have to say that I have been demoted all the way down to Silver 3. Most of which is due to teammates raging and going AFK and the game becomes a 4v5. literally 6 out of my last 10 games have been that. I understand that a loss is a loss and that there are bad games, but the rate that it happens is ridiculous. I don't think it is fair that teams that are forced to play 4v5 still lose just as many points and one players decision effects the rest of their team.

Like I said I know there are bad games, but I find it stupid and it ruins the game.