In the days leading up to Wednesday’s attack on Twitter, there were signs that some actors in the SIM swapping community were selling the ability to change an email address tied to any Twitter account
a user named “Chaewon” advertised they could change email address tied to any Twitter account for $250, and provide direct access to accounts for between $2,000 and $3,000 apiece
“This is NOT a method, you will be given a full refund if for any reason you aren’t given the email/@, however if it is revered/suspended I will not be held accountable,” Chaewon wrote in their sales thread
https://krebsonsecurity.com/2020/07/whos-behind-wednesdays-epic-twitter-hack/
The New York Times followed by interviewing two people purportedly linked to the security meltdown, both of whom cited a hacker who went only by "Kirk" as the central player here
https://www.nytimes.com/2020/07/17/technology/twitter-hackers-interview.html