I received a message online, by someone saying 'vengeance is coming'. I know this person, we fell out about 6 months ago and I don't live very far from them and my business is situated not very far from them either. I'm not really dealing very well with this. I just need some advice on what I can do. They were slandering me about 4 months ago on Facebook in posts and I thought it had stopped and I've just seen this message from them. Any advice on where I stand with this? I don't know whether I actually have any case if I take it to anyone as it's just one message. But it's a pretty upsetting one.