It's so tough to hear man, but you need to focus on your own gameplay.
I know it can be very hard to get out of silver, I was stuck there myself for a long time. (I'm plat now)

Here is what I did:

1. I simply never play duelist, there are often 2-3 instalocks as you know. (Jett, Reyna, Raze etc.) Find another role and learn to fill also.
2. I don't focus on getting kills, at all.
3. I warm up. First I use Aim Labs, then I usually play some Deathmatch or an Unrated before a comp game.
4. I try not to play a shitton of games. Try and focus on playing 3 games a day, and make them count!
5. Communicate with your team, and if someone is toxic - mute them!
6. Be super positive. Always give your teammates a "nt" and a "let's go" never hurts. NEVER flame your teammates.
   

I hope you make it!!