Phone Number Not syncing

This has answered before but I still continue to face the issue where for some reason the phone number is not getting exported to Mailchimp. As suggested before I have added the following code to the functions.php file but it still does not work:

function mailchimp_custom_order_merge_tags($merge_tags, $order) {
// the phone number can be used from either the shipping address, or the billing address.
//$shipping_phone_number = (string) $order->getShippingAddress()->getPhone();
$billing_phone_number = (string) $order->getBillingAddress()->getPhone();

// this is what I would do – only supply it if the phone number is there.
if (!empty($billing_phone_number)) {
$merge_tags[‘PHONE’] = $billing_phone_number;
}
// return the merge tags to be submitted.
return $merge_tags;
}

add_filter(‘mailchimp_get_ecommerce_merge_tags’, ‘mailchimp_custom_order_merge_tags’, 10, 2);
?>

One more question – if someone checks out without creating an account then will address and phone be picked?

Please help