Unpaid Refund/Bad Customer Service

I have had an ongoing query for the past six months. I ordered a pair of sandals from Farfetch, but they were never delivered due to the driver being hijacked. Farfetch has since refunded me in full; however, FedEx has failed to reimburse me for the duties I paid.

I have contacted customer support multiple times, but the assistance has been extremely disappointing. Initially, I was told that my issue had been logged and that payment was due. Since then, I have received no further updates, and my emails are now being ignored.