What legal action should I take against a blackmailing?

Hello, one month ago, I joined a color prediction game on Instagram, where I invested ₹100 and earned ₹1,500. I later added more funds, and there was a requirement to add more members for additional rewards, which I did. My friends and I made good profits for two months. Unfortunately, we lost all our remaining funds. Now, one of my friends is abusing and threatening me, blaming me for her loss, and has posted on social media with my photo, accusing me of cheating and demanding money. I later discovered she used her husband's money to play. What legal action should I take? She is now blackmailing me, despite my repeatedly telling her that I did not force her to join the game, I only made the proposal.