Ugh, that's the worst part about traveling now. The security is so tight it locks you out of your own money. You'd think they'd have a better way to handle this by now.
My friend had the same thing happen in Bangkok last year. Banks have these crazy fraud algorithms that flag any login from a weird location. Using a VPN makes it look like you're suddenly in Germany or something. They freeze everything just to be safe, which is a huge pain when you're traveling. You basically have to call them and verify it's you, but international calls are a nightmare.