Promo Games and Trolls

The last 5 times I've been up for promotion I've gotten THE WORST trolls in league and I've seemed to notice a pattern. I get 16 points for a win, 20 for a loss and when I lose a series I drop to around 64 LP. I've been silver 3 for over a month now and I can't seem to dodge the d/cs and afks. I can carry some of the baddies on my team but I feel I can't get out of silver with this points system and afks. Does anyone have any advice or knowledge toward the points system?

Its funny how after I make this post I get promoted, BUT in both my promo games we had an afk for the first 5 minutes. I'm so lucky that they were not gone for longer. It doesn't make sense to me that promo games are harder because it gives me a feeling that I'm playing above my skill level, thus meaning I feel I should skip tiers OR they should give me a normal game where I'm "supposed" to be at.