hi. that is very odd. before the browser invokes the coinbase buy widget, it checks to see if your IP address corresponds to a US location. if that is the case, then the “Fund with debit/credit” button takes you to the coinbase widget; otherwise, there are other options.
so it seems like the geo-locator used by the coinbase widget is mis-identifying your location. in the short-term your solution is the VPN. it’s probably worthwhile to file an issue with the folks at coinbase to let them know about the database issue.
although the coinbase buy widget solves a lot of issues, there are some hiccups, and this looks to be one of them…