I am sorry that you are having a rough time with your neighbour - despite dealing with neighbour disputes for a number of years, I still can't resolve my own! However unreasonable your downstairs neighbour's behaviour seems, she will have a reason (in her mind) why she is behaving this way. If she has a personality disorder it may be something you and I might consider off beam but to her it will justify her behaviour. I have dealt with situations where the placing of a piece of garden furniture lead to a serious neighbour dispute, so don't underestimate how seriously someone can take even the most innocent actions. It may even be that her dispute is with the previous tenant or owner. You can speak to your landlord or the agent but I am not sure what they can do as much of what you have described is inconsiderate or odd behaviour. If you are friendly with your neighbour you can usually sort this kind of problem out by speaking to them but (as I know in my own circumstances) if you aren't, it doesn't matter who speaks to them, the problem will continue and may get worse. I would caution against playing tit for tat - ie blasting out loud music - as it won't really make you feel any better and may end up escalating the situation. You could report her to the police but she will probably deny she made the threats and unless you can prove deliberate harassment they won't want to get involved. Others have mentioned mediation, which can work, but you would both have to agree to attend. If you haven't already, why don't you do some research into this as it sounds like the only option. As you are renting it may be the best option to prepare yourself to move. I know there is an element of 'why should I go - I am not the problem' but there is a danger that these disputes can take over your life and end up affecting your health.