Clarification on the Declarant's Information for the C285 Form

I recently bought a jacket for £133 (all costs included like delivery) from France to the UK and was mistakenly charged a customs duty of £52.71 by DPD for a purchase under the £135 limit because they have done the declaration in euros (160euros). From my understanding, to get a refund I need to complete the C285 form. However, when I go through the steps, it asks for the declarant’s name and EORI number. Is the declarant me, DPD, or the company I bought the jacket from? Where can I find the EORI number, as I am an individual and do not have one? I also asked DPD, and they said they do not have this number. Please could you help me complete this form or report this as a bug to the developers? Additionally, I tried to find a PDF version of this form but couldn’t. Thank you for your assistance.

Hi,
Declarant is the agent or express operator who has submitted the declaration on your behalf. If DPD has submitted declaration and paid customs charges to HMRC on your behalf it will be them who is the declarant. You may need to contact them again to request the information. 
Guidance on what information is required for C285 form is available on below link.
How to claim a repayment of import duty and VAT if you've overpaid
Thank you.