AliExpress Refund Denied After Return via Klarna

I ordered a Two Trees TS1 Mini laser engraver from AliExpress and paid £57.58 via Klarna. After receiving the device, I realised within a couple of days that it was not powerful enough for my needs, so I requested a refund and followed the returns process. The seller rejected my refund request, but AliExpress stepped in and decided that I should receive a refund around 7 November 2025. I returned the product and I have proof of posting, but the item was apparently lost in the post. Despite this, I have still not received my refund, and I am being denied a refund even though I can prove that I sent the item back as required. I am based in the UK and I request that AliExpress and Klarna process a full refund of £57.58 and ensure the Klarna payment is adjusted accordingly, as I followed the return instructions and can provide proof of postage for the returned laser engraver.