My Competitive Placements were ruined by hackers multiple times on the enemy team and leavers despite me playing extremely well getting most of the medals during most of the games I still lost obviously , i understand its not the game’s fault for players who leave, but the hackers were still there. This was my first time ever doing placements on my account, i was matched against high level platinum and diamond players, I played well but I still got placed into Gold at somewhere in between 2100 , I didn’t even get to do my placements properly as out of the approximate 10 matches I played yesterday at least 4 of those games had a hacker or not counting the leavers , I couldn’t even get help from the overwatch support website for this issue 
As long as you reported them in game, there is nothing more you can do (and nothing more blizzard want you to do).
Luckily you were only doing placement. The results of these matches are not too relevant. As first time it’ll just be around your MMR. And in future seasons you’ll be place roughly where you finish each season.