If I need to ask the customer to provide additional shipping fees under special circumstances (for example, the customer would like express shipping for their order), how should I do this?

You can list the item as an “Additional Shipping Fee listing” with the required shipping fees and then ask the customer to order it.

If the extra shipping fees are not a result of customer requirements (for example, you accidentally set the wrong shipping fees), please contact the customer via Pinkoi message as soon as possible. Make sure that you come to an understanding with the customer in order to avoid any possible disputes.