Well, it was simple for me. You should download some browser VPN like Hola! or something like that, and turn it on in your browser. Log out, and then log back in. It worked quite nicely for me. Now come to your profile and see your country code. If it's the country you selected, then good job, close the browser and then see your flag. It should be that country
Most VPNs only support US/UK/AU mostly, but if you moved to another country, just wait. It will detect your country after some time.