How do I deal with someone who is blackmailing me with private messages?

Dear sir I have been blackmailed by an unknown person called simran jain (fake id i guess) by sending private images n messages by hacking my account to my friends n family. Will you pls take the needed action? This is the number where he/she whatsapp me n blackmailed me. whatsapp number used to blackmail me: +91 6301 136 280