My girlfriend suddenly hacked me. I don't even know what happened. Don't answer the phone, don't reply to text messages, WeChat blacked me out. What should I do now?

If your female best friend suddenly blackmails you now, you don't even know what happened now, and now the other person doesn't answer the phone or return the text messages. And wechat is still hacked. I think you can contact in other ways now, if you really can't. Then you can contact him through other friends. If you know where his home is, you can go directly to his home and ask where it is. If you don't do anything now, it's bound to go away.