Are you renting from your local authority? are they living there long, have any other neighbours mentioned the neighbour being a bully, I'd report the person to the landlord if you are renting, I'd let your gp know, it can't be good for your mental health and if you have family close tell them, you must be in a desperate state. As suggested keep a diary, verbal abuse is disgraceful and while I can't help legally or advise, I know they may not need to phone you, just their demeanour that no one else can pick up on can be hurtful, I have a friend, in her 50's going through the same in her workplace, no one sees it and sometimes she feels she is going crazy, after keeping a diary, telling people and keep going to her bosses, she's now on paid leave while they deal with the bully. You need to let the bully know others know about them, that you are not alone and they won't intimidate you - best of luck, I know it can't be easy