Continually re-open the ticket by responding to it by email and anything else you can and they eventually have a human check it. Discord, ironically, is terrible for gaming chats now, because there are so many basic things, like discussing weapons, killing other players, or ingame suicide, that can get a server taken down. It's basically all automated with a ban first and check later policy.

I can recommend Cinny, one of the most advanced Matrix clients, as a replacement, if your users are willing.