Retrieving customer information to use in drupal commerce payment module
The customer profile is attached to the order, and it has an address field that holds the information. To get it you could do;

$order_wrapper = entity_metadata_wrapper('commerce_order', $order);
$address = $order_wrapper-&gt;commerce_customer_billing-&gt;commerce_customer_address-&gt;value();
$postal_code = $order_wrapper-&gt;commerce_customer_billing-&gt;commerce_customer_address-&gt;postal_code-&gt;value();
...


It's a lot simpler to use the entity metadata wrapper as shown above. What it does is that it loads the customer profile entity for you and let you access it's field.