Apparently, they don't really need clients: I called 3 times at different times: the first time it was busy, the second time no one picked up the phone, the third time the girl picked up, said she was on a call and it was inconvenient for her to talk, but in none of the three cases did no one call me back.
I added an asterisk only because I knew about them based on a recommendation, but I don't want to get involved with this approach to work myself.