I will add my bit to this thread. Remember as you have been told there is NO AGENT/AGENCY to apply for US visa for you. Whoever that comes to you or sends you a message claiming he/she/they can do it for you provided you "pay" for their services is trying to scam you.

Again the only place to apply for visa is online (as stated previously) and once you apply and get an appointment you'll have to go to the US Embassy for final interview.

Regards!!