Now I’m having nightmares about my clients

So this client keeps stressing me out. She calls several times a day. She doesn’t want to take my advice so I don’t know how else to help her. Unfortunately since the pandemic all my work calls are forwarded to my cell phone so I know when I’m getting a call after hours. She called me at least 6 times in less then 2 hours. I didn’t answer as I do not work weekends. This woman has no boundaries. I am sure when I call her Tomorrow she will complain that I didn’t take her calls or call her back yesterday. I want to just go off on her but I know I need to remain calm and simply tell her she cannot get me after hours and I won’t allow her to consume every bit of my time. I know I need to say it delicately but at this moment I don’t have the words to be nice.