The official source for every statement made about eligibility, cost and timing; exactly what services the fee covers; what happens to any payment if the applicant withdraws or is refused; and whether the intermediary is authorized to represent applicants. Answers that cannot be given in writing are answers worth noticing.
Ask for citations, not assurances
A straightforward request settles most of these conversations: for each claim, name the official page, regulation or statute that supports it. Legitimate advisers answer that easily because their advice is built on those sources. Ask separately about money: what is payable, when, to whom, and on what terms it is refundable, with an engagement agreement rather than an invoice. Ask who will actually prepare and file anything and in what capacity. Then take the answers away and check the sources independently rather than in the same conversation. If a deadline appears at the moment questions are asked, that timing is information about the pitch rather than about the program, and an owner who would never buy a machine on that basis should not buy a status on it either.
Hypothetical example: a municipal-water sensor founder wants to act quickly after receiving a marketing presentation. A first review saves the dated official program page, any published instructions, proof of identity, source-of-funds materials and the actual payment directions. Those official materials settle what must be submitted; promotional slides do not. Keep bank records that show funds leave the applicant and reach the U.S. government if a payment is made. Because the program is not a conventional visa, do not borrow document assumptions from EB-5 or E-2.