I believe the shipper is paying all charges

In order for FedEx to invoice the shipper for all charges incurred on a FedEx Express International shipment the shipper needs to indicate 'Bill Sender' for both Transportation and Duties & Taxes on the FedEx International Air Waybill.

In the vast majority of cases the shipper will only take responsibility for the Transportation charges and if they do not select a billing option for Duties Taxes on the FedEx International Air Waybill.

The default will be Bill Recipient for any Duties Taxes levied on the importation by Customs. Therefore, in the majority of cases when the shipper has made payment to FedEx this only relates to the Transportation charges.

In addition Duty and Tax charges are not assessed until the shipment enters the CZ so FedEx are unable to advise the shipper of the import Duties and Taxes at the time the shipment is sent.

For more information on Duties and Taxes please visit: https://www.fedex.com/cs-cz/billing/duty-tax.html