make sure you write down times, dates, people present and things said for future reference. this kind of documentation is also crucial when reporting harassment and threats to the police. people are generally stupid and if they deny doing this and try to lie about 'i wasn't there' or 'i was at the pub' etc., things like cctv or work schedules etc. will discredit them and what they are saying in their defence. do not antagonise them, try not to say anything dodgy yourself and keep a low profile if you can. if they keep it up and you present decent records, recordings and/or other evidence you will be able to take effective action against them (like an injunction, or pressing charges against them for harassment if they persist). i repeat - times dates, places etc. are CRUCIAL for you to be able to defend yourself against idiots like this. and they are idiots - they will catch themselves out, if you let them.