Having a similar problem to others in validating my sons account on his new Nokia Lumia 620.  Contacted MS help and got pushed back to the forum.  Picked up a phone number to call and that was pointless.  Really think that MS post needs updating!

So the problem is:

New UK purchased nokia phone. I have an account to authorise from but when I try is rejects the card number as non US based because the default seems to be to the US [ which given MS is a multinational organisation and product is rubbish anyway]

The phone is certainly UK registered I checked.  Likewise son email has a .co.uk extension and as the shop set up his MS account I think that will be UK based. 

Any suggestions?