Can not input United States for my billing address

I attempted to download the Rhino 7 for Windows student version and chose the buy online option. However, it will not let me input the United States as a billing address. I am an American student studying abroad in Italy, and that is the only way I can purchase it.

If you’re in Italy, you’ll need to buy your license in Europe.
Barcelona is the Regional HQ.

How can I pay if my cards have billing addresses in the United States?

I would think that if you can use your card in an italian restaurant it ought to work for the Barcelona HQ.

The form directs you to input billing address, and the billing addresses are in the States. If a family member buys a Rhino license in the states, could I download the license here in Italy?

That should work.
You can download the installer from anywhere.
You can purchase a license in the Region you are in.
The license comes in an email message.