Why am I consistently failing my promos?

Hi all, this past Saturday I made it into my first promo series to get into silver 4 some bad players ruined it and I was left in Silver 5 again. I thought ill get it next time and 8 promo series later I'm still in Silver 5. I feel that if im good enough to make it into my promos 8 times in the past 5 days and fail them all that there's something wrong. Its not that I play poorly in my promos either, I get a very high probability if trolls, afks, and dcs in my promos in comparison to normal ranked games. In the past 8 promo series ive been in, I think only 2 games we're legit losses without and trolls, afks or dcs. So I'm curious to know if im just unlucky, or is there a flaw in the promo matchmaking system? Also I think that riot should implement a system that automatically promotes you to the next division if you make but fail your promos multiple times in a short period (Ex: Qualifying for 3 promo series in 3 days) . Thoughts?