You might have better luck looking for an international brokerage that can let you transact in the US brokered Certificate of Deposit (CD) market. Many of those offerings are also FDIC insured, and the marketplace dynamics may mean the bank only transitively vets the customers, and brokerage vetting may be more flexible?
Of course, a lot of US brokerages also don't want to work with customers who don't live in the us and/or aren't authorized to live in the us.