Honestly, it is my first time to see such blackmail email. And the first thing that I wanted to ask is,

Is it true that you all did what that sender told?

If so, you were definitely tricked and found your weakness. But despite of that, Never Ever send such amount to that blackmailer. This will just tolerate him.

There's a third option:
-Report to the authority
Don't be scared. They can definitely find that sender's IP address and track him down.

As long as you do not send any amount to him, then let him just blackmail you. Change all your  passwords in all of your accounts, reformart your computer to clean all the malwares inside. And this should be a lesson learned to you not to click and download any suspicious sites, links and apps.