Advice on narcissistic MIL

I would love some help! My MIL is SEVERELY narcissistic and my husband and I are trying to deal with her. She's manipulative and controlling among many other things. My husband and I have been pulling away and setting boundaries because we really don't want the negativity in our lives. She is feeling that we are distancing which is causing her to call/text constantly. We tried ignoring her but it seems like it's making it worse. She's impossible. I would love to have no contact with her at all but we aren't at that stage yet, I think it might be getting there pretty soon though. My husband is in therapy to work through all of the twisted shit she put him through as a kid and it makes me sick to my stomach finding out some of the stuff she's done to him. Thanks for reading and any advice you can give is appreciated!