DDoS Ransom E-Mail: black shadow group

A blackmail e-mail from the black shadow group has just arrived at a customer:

FORWARD THIS MAIL TO WHOEVER IS IMPORTANT IN YOUR COMPANY AND CAN MAKE DECISION!
We are the BLACK SHADOW hacker group.
Your network will be DDoS-ed starting 12:00 UTC+1 on 08 May 2021 if you don’t pay protection fee – 10 Bitcoins @ 1FfmbHfnpbZjKFvyi1okTjJJusN455paPH
If you don’t pay by 12:00 UTC on 08 May 2021, attack will start, your service will go down permanently. Price to stop will increase up 5 BTC for every day of attack.
This is not a joke. We are the BLACK SHADOW liberty hackers.
Our attacks are extremely powerful – sometimes over 1,3 Tbps per second. And we pass CloudFlare, Link11 and others DDoS protections! So, neither cheap or expensive protection will help.
Try to reply, we will not read. Pay and we will know its you.

Mail black-shadow@protonmail.com

In fact, about 200GBits ingoing traffic on the uplink. Mainly UDP traffic. We had to blackhole the attacked IP addresses from the network and put new IPs on the services. Everything was back online in an hour when the traffic in DeCIX was thrown away by their routers due to the null route. Fortunately, the attacker did not react to our evasion technique.