What legal actions can I take against ongoing harassment and defamatio

A girl I was in a relationship with over 18 months ago has been continuously harassing me ever since we broke up. Recently, her actions have escalated to a point where they are seriously affecting my personal and professional life. She has created multiple fake Instagram profiles and email addresses to contact people I know, spreading false and defamatory information about me. A few months ago, she even reached out to my workplace with fabricated allegations, attempting to tarnish my reputation and get me fired. Fortunately, my organization and colleagues stood by me, and no action was taken against me at that time. Now, she has emailed me, apologizing and expressing a desire to reconcile, but at the same time, she has continued to create fake accounts to reach out to people I know, particularly women, to damage my image further.