avidpassenger

Hello there, I would like to return a pair of boots I purchased in an online store back to Poland. I already paid a customs/duty fee to DHL prior to delivery. So I wanted to query: 1) If I'm send the goods back to Poland (via Royal Mail), would the retailer be charged any import fees? 2) Regarding form C285 a) Do I need a EORI and/or MRN number (I can't see any on the DHL invoice)? b) What would I put as the "Declaration date"? c) What do I put for "Is the Importer a Private Importer"? Thanks in advance