Biological Parent Is Destructive In My Life

I was placed in foster care at the age of three. I lived with this family for five years prior to being adopted. Life wasn't perfect, but it wasn't terrible.

My biological mother entered my life again a few years later, and it was okay for the most part. However, over the past many years it has become increasingly difficult dealing with her to the point that I just stopped.

My issue is, she continues to poke in my life and send harrassing emails. She stalks my kids by setting up fake social media pages, following them, and then sending messages. I keep telling her to refrain from communication, but she continues. My kids have seen how ugly and destructive she can be with her words, and rather not be bothered as well.

She is mentally ill, and even receives social security disability, but it gives her no excuse to continue with her shenanigans.

What is the best way to overcome this aggravation? How can I get her to stop?