What to do if someone keeps blaming the other person?

Hi, I am an IT professional working with an mnc in pune. The problem is related to a girl who was my pg roomate. Before moving to Pune, I was in Mumbai for 3 yrs, and this girl was my pg roommate for around six months. The problem is she thinks that, since I am an Android developer, I have hacked her phone from six months, and I read her personal n professional msgs. I listen to her all incoming and outgoing calls. I am the reason that she is not getting any job. She thinks that I am in contact with her ex boyfriend and I am creating all sorts of trouble in her life. I don't have any issues if she keeps on thinking all these, the problem is she is telling my pg frends that I am doing all these things. She is spreading all these nonsense about me. Now she has crossed her limits, she called up my husband and talked all these nonsense to him. She sent him quickheals's app screenshot and told him this quickheal symbols means, my phn is hacked and I am doing all this. Now tell me what to do? What to do if someone keeps hallucinating? What to do if someone keeps making stories on their own? This is causing mental stress to me. Pls help me, and provide ur suggestions. Pls pls pls.