Ask HN: What can someone do if their SNAP account and videos are hacked?

Hello HN, I'm creating an Ask HN thread due to a weirdish reason. A female acquaintance of mine who works as a model reached out to me because one of her friend's Snapchat account has got hacked and the person who has hacked their account is in possession of sensitive material belonging to them and is threatening to make it public. The person who has been hacked is somewhat famous and is worried about nuisance value and loss of reputation amongst other things if the video gets public. Is there someone from SNAP here who could help them? They have the hacker's Snapchat ID and proof of being threatened over a snapchat chat.