almost got my Twitter banned
You give details, they log into your account, they search the keywords you've already given them and then they follow HUNDREDS of people who use those keywords. Waste of time as you end up with a feed full of unsavouries spouting racist or sexist crap.
Steer clear, it's not worth your time, effort or money.
You do not get very much followers on this service, I have tried it for two months, and I have barely seen more followers on either of my accts. Just a massive increase in who I follow. You can do this yourself and probably get more followers.
Grateful for putting me in touch with other brands!!