Falsely accused of question?

my friends partner has been accused of by their neighbour. the thing is we know it never happened as the time it apparently happened, my friend and partner and children were on holiday. the police were called and have confirmed the lady is lying. what i want to know is.....my friend and partner are now getting abuse, things being thrown at them, car being vandalised and now their cat has gone missing for the first time ever.....my friend is petrified to leave the house and the police dont seem to be doing anything about this...is there anything they can do? its completely not fair and its ruining their life