In September 2014, a group calling themselves DD4BC (DDoS for Bitcoin) began sending CFOs and CSOs emails stating, Pay us or else, and threatening to bring hundreds of gigabits per second of traffic to bear against organizations. Copycats have sent out emails mimicking the emails of the group calling itself the Armada Collective. The most recent high-profile target has been secure mail services such as ProtonMail. In my opinion, paying a ransom is a mistake, though the attacks have continued.”]
Source: https://securityintelligence.com/pay-us-the-money-or-the-website-gets-it-extortion-by-ddos/