Zoho Flow and Woocommerce Custom Checkout Field Meta

Zoho Flow and Woocommerce Custom Checkout Field Meta

We have a custom checkout with custom fields.  The plugin works with Zapier and when you link Woomcommerce you can see all the custom field data.  Using Zoho Flow only shows the standard Woocommerce meta data and none of the custom fields.  I wonder what difference there is between the Zoho Flow connection vs Zapier which causes the data to not be seen. 

We've contacted the developer of the plugin who has said the following:
The fields created using our plugin are saved in the wp_postmeta table. You can retrieve the value of the custom field from the database by using the below function.
 
For order metadata, you can use the below function:
 
$order_meta = get_post_meta( $order_id, $field_name, true );
 
If you configure the field as User metadata then those fields are saved in the wp_usermeta table. You can retrieve the value from the database by using the below function.
 
$user_meta = get_user_meta( $user_id, $field_name, true );


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I just wonder whether anyone can help us implement the custom fields so they are viewable from Zoho Flow??