Refund of Duty and Tax incorrectly charged

Hi, I applied for relief on importing my personal belongings from Ireland to the UK via a ToR1 form. this was approved before shipping my personal belongings with FedEx. Despite my URN being on the form, FedEx have charged me for Import Duty and Import Tax. I acknowledge that perhaps I didn't do something correctly, the instructions for what to do afterwards are unclear (and no information is available from FedEx). I am wondering if I can claim both the duty and tax back, as I have been approved for relief on those items. If I am, how do I proceed with this? I have already contacted FedEx, and they have not responded. I assume at this point the money has gone to HMRC. Many thanks in advance!

Hi.
Please send all the relevant information with your claim form and you will get an outcome by the case working team. 
Use form C285 if you believe the Customs Duty or import VAT was wrongly calculated on an item you imported by post using any other courier:
How to claim a repayment of import duty and VAT if you've overpaid
Thank you.