Twitter shuts down Crowdfire, Statusbrew and Managefltter

https://blog.smarterqueue.com/alternative-to-crowdfire-twitter-api/

RIP even though most of us stopped using Managefltter when they limited the free version from 3000 unfollows a day to like 20 a day.

FYI this has nothing to do with buying followers.

If buying followers for public profiles actually hurt the account or violated the terms, then that means I could buy followers for anyone and get their account banned. (Which would be overpowered and doesn't work since all you need is a username.)

Be careful not to mislead yourself into thinking that buying followers will get your account banned. It won't.

The ban stated in OP was because of something completely different.

Never said it was for buying followers. You can't buy followers on those sites...

They got shut down for aggressive following/unfollowing tactics.