Is there any ways to get someone thats mentally ill to stop harrassing you?

i have a neighbor like that, god forbid i come out of my apt when shes out there, she'll complain im staking her,she complains if i have my door open, like im trying to come out when shes there and im not, i just didnt feel like taking my keys with me, then her friend comes and tries to get a picture of my open door, and i heard talking out in the hall so i opened the door cause i thought it was my other neighbor who i was friends with and i see her friends with a camera trying to take a picture so i slammed the door on her, that mentally ill person is telling my apt manager i went to her place and ripped up her jacket, i did no such thing, if shes going to be paranoid like that she needs to keep it to herself, how do i keep her from harrassing me and telling on me when i did nothing, she belongs in the psych ward , not in my building next door to me