You can achieve disable billing address by using the hooks in functions file of wordpress theme.Use these two hooks below:
add_filter( 'woocommerce_checkout_fields' , 'remove_billing_fields_from_checkout' );
function remove_billing_fields_from_checkout( $fields ) {
$fields[ 'billing' ] = array();
return $fields;
} add_action('woocommerce_checkout_init','disable_billing');
function disable_billing($checkout){
$checkout->checkout_fields['billing']=array();
return $checkout;
} 
