I played 2 games, in both of them hackers ruin the game and 1 shoot headshot.

Hi there, I'm sorry to hear about your experience. If you suspect that you have found cheaters in a match, please make sure to report them using the in-game tools. You can find further instructions here.

I play as Specialist main and the NT-242 is the only weapon that one-shot headshots players, so I do it when I can... BUT .... the cheaters in here who get 56 headshots during a round of Blast are insane and ruin the game as much as all the rocket troopers. 

grrr33nflash​ I'm sorry to hear about that! Please always make sure to use the report tool if you suspect someone might be cheating.