Receiving death threats on an online game app what do I do?

I am part of an online game where there is communications between players via "telegrams". There is an individual that is sending death threats and telling players he will find them and kill them, kill there grandmothers, rape there mothers, some of the players that are receiving these threats and messages are around 12 years old. Many of us are a part of the community forum for the game and we have expressed our concerns with the community manager but he refuses to do anything about it. Is there someone that I can talk to at apple that would be able to assist us with this problem? When I say us, there are many I am just speaking for everyone.