Solved replacing this code:
<?php foreach ($checkout->checkout_fields['billing'] as $key => $field) : ?>
<?php woocommerce_form_field( $key, $field, $checkout->get_value( $key ) ); ?>
<?php endforeach; ?>
for this one:
<?php
// order the keys for your custom ordering or delete the ones you don't need
$mybillingfields=array(
"billing_first_name",
"billing_last_name",
"billing_company",
"billing_address_1",
"billing_address_2",
"billing_city",
"billing_state",
"billing_postcode",
"billing_country",
"billing_email",
"billing_phone",
);
foreach ($mybillingfields as $key) : ?>
<?php woocommerce_form_field( $key, $checkout->checkout_fields['billing'][$key], $checkout->get_value( $key ) ); ?>
<?php endforeach; ?>
https://wordpress.stackexchange.com/questions/78339/how-to-reorder-billing-fields-in-woocommerce-checkout-template
I dont know why but the original foreach dont work correctly
