This is more serious than I thought it was.
The fact that it is not only the email but also the phone-numbers of the people are allegedly for sale means the possible buyer could have the chance not only to go for a classic fishing campaign but also more elaborate kinds of attacks like SIM-swap or even go as far as de-anonymize those who are deemed "rich enough" in order to get them to pay through extortion.
I hope this ends up being false, but just in case, I recommend anyone reading this to treat your Twitter-linked phone number as compromised and delete it as 2FA on your exchanges and bank accounts, as soon as possible until this gets confirmed or debunked officially.
Merry Christmas
Sure it's a serious case, after all, data is the most expensive and important thing on the internet and I'm sure the person who got all this data and especially the phone number of the users can sell the data for a very good price and can earn huge money from it, also, once again we can see a famous company is under attack by the hackers and they failed to prove enough security to protectthe people information, that's why I always suggest my friend to use fake information in social media.