I really don’t have any good service that isn’t be a total pest back, because that’s honestly the only way I’ve ever resolved situations like this despite multiple attempts at fair communication like you’ve done. Offering condolences though because I absolutely agree that part of apartment living is consideration of others. Families should second guess getting second or third story floors and so on. My neighbor’s kids do the exact same thing and they’re over 10 years old, one is a heavy kid. He has literally broken light fixtures in my apartment from throwing himself around so fucking hard. Nothing ever gets through to them except the times I’ve woken them up at 4am because that’s when I need to get to work and I might as well be loud if they’re inconsiderate too. They don’t pick up after themselves at all, they have several dogs and cats, and they love to wash their shitty stinky ferret supplies in the only communal washer and dryer we have. Also very insistent on keeping the communal door open so their dumb little doorbell camera can watch everyone and so they can vent the nasty ferret and BO smell. Since their windows apparently don’t exist. Gotta hear arguments late night about who isn’t stepping up as a parent and who’s been the absent one (surprise it’s both of them!)