If you paid a consultant and suddenly your number of followers greatly increase, aren't you a bit naive to think this was due to genuine interest ? Even more so, if you are positioning yourself as a cybersecurity expert.
The interesting point was about the lack (or ban from) of twitter account and potential career prospect.
I'm with you apart from this sentence. What can you do after the damage was done? I'd assume they thought the consultant was legitimate, the opposite proved to be the case, and the two of them had no idea what to do afterwards. Ask bots to unfollow you? Create a new account and lose the legitimate ones you'd have regardless of this? Admit to Twitter's support that you gave access to someone illegitimate?
Their situation admittedly sucks, but I have no clue how would I undo the damage if I made the same mistake.
This. On the old account, tweet something like "I worked with a consultant who turned out to just sell fake followers. I want to leave those behind, so please follow my new account @foobar instead."
An uneducated assumption: that freelancer gave API access to some app usually used by Chinese propagandists, Luka and his father didn't go through the authorized apps since, and Twitter decided to really not dig deep into this false positive, but superficially confirmed that this account indeed gave access to some app that it shouldn't have.
Either he bought followers, or gave suspicious apps authorization to post on his behalf, or his account was hacked.
None of the three seem good.
In the latter two, Twitter could easily prove that he was part of the influence network by producing the tweets that were made via his account.
And buying followers is against TOS (but do they ban people for that? #doubt), but certainly not everybody that has fake followers is declared to be an actor in a state-sponsored misinformation campaign.
China News Service invites paying some 1.25 million yuan for 580,000 followers.