Yelling and screeming on kids

I want to know that since many time two individual from the society yelling on kids saying that children's cant play at play area after 10. Yester one incident went where kids are playing that guy yelled on them and due to that sudden scream my daughter fell down from the slide and crying and shivering a lot. Kindly help us in this matter what can we do

Our society has 140 flats rest 138 flat members has no issue but this 2 flates mates are constantly doing the sMe thing