He doesn't have all the information. Another extremely important reason to clear this up: if Chase reports this as a 60 or 90 day default this will plague him for seven years. HSBC did something like this to my wife (also due to autopay, despite her having plenty of money) and her credit was hosed for seven years. They refused to correct it later on.

You can call the US via Skype for free. This isn't only a matter of losing a relationship with one bank. Unlike other shutdowns it could prevent him from getting cards from many banks if they report it to the bureaus. Which we have no reason to think won't happen if they really insist on interpreting this as a failure to pay. Which they are saying they are.