Didn't work for me either...
I used a proxy from https://www.hidemyass.com/proxy-list/search-3#browsersettings

I got informations about my IP on the web to verify if it was located in US, and it was.

I keep receiving the same annoying message:
We are sorry...

We could not process your order. The sale of MP3 Downloads is currently available only to US customers located in the 48 contiguous states, Alaska, Hawaii, and the District of Columbia.

We apologize for any inconvenience this may have caused you.

Any suggestions?
Thks!