Help my neighbors are complaining?

They just moved in like a month ago. they live above us and their kids STOMP all day long. running up and down. we don't complain. one night my mom turned on her music it was only 8pm and it was playing for 30min. and they called the police, this was 2 weeks after they moved in. the cops came and left. the next day they let their kids stomp all day long, so we put our music on LOW. this is around 12p.m. ..our stereo speakers go up to 100. we had it on level 10! and they started complaining, stomping across the ceiling as if their signaling us to low it. we called management and had them come in our apartment and they said the music wasnt even loud, can we file a complaint against them for harassment. i mean, if they don't want to hear ANY NOISE at all then why move into an apartment complex? your gonna hear something..buy a house or a condo or something if you don't wanna hear noise through the walls.