Can't sign up to closet child.

For the past hour i've been trying to sign up to closet child, otherwise i cant complete my order..
but it just wont take my zipcode/postcode at all, i've tried several ways of putting it in.
i've also tried the 00000 code closet child tells you to put in if yours doesnt work, and it still wont take it >.<
Has anyone had this problem before? and is there a way i can solve it?