For a long time these "buy/sell" upvote services have stopped working on steemit (at least, as far as I know).

I believe that before you send money anywhere, you need to make sure that it will be received effectively and that your money will be valued.

When you try to buy votes, your money is not being valued, you are not even valuing your own work. You should focus on having your own fan base, actively belonging to communities, participating in Steemit initiatives and challenges, things like that.

Lastly, I don't think many Steemians are sending money to these accounts, as everyone knows that vote-buying ended 2 hard forks ago.