Try contacting them via texting or e-mail. Inform them you want to be screened to join their client ranks. Then submit your screening info like two current references and whatnot. The worst they can do is ignore your request. That happens to me now and then. The agency or provider never answer back. That's fine: the money stays in my bank account. They can't turn their backs on you AND take your money. Rejection will never translate into profits.