To all those whom are Xbox wizards: Help?

My friend used to get on Live and play together all of the time. We both have a mutual enemy that will hack her account sometimes. Well, when her Live ran out not too long ago: she went to pay it but it asked for payment in euros. Somehow her country was changed to the United Kingdom and she can no longer get onto her account for anything. Can someone tell me how to change it back? Both of us would be very thankful.