Cocosa complaint: Refuses to refund me for goods which they failed to delivery to me

Placed order in On 5th October on the website. Goods were delayed abd dispatched when I was out of the country. I had left no instructions for the goods to be left in a “safe place”, however Courier left them in an unsecure place in full view of passers by. When I returned from holiday, I found the card from the courier through my letterbox and no parcel in the place where they had left it had been stolen. I contacted Cocosa immediately 21 Oct and provided them with evidence of me being out of the cohntry ( and therefore not able to receive parcel) and the Hermes card saying parcel had been left in the meter box. I also provided photos showing the position of said box and it’s access to public. Cocosa have ed with hermes that the parcel was left in the box (without my permission) and that I am due a refund, however they are refusing to provide me with a refund 6 weeks later, saying that they are waiting for Hermes to provide the refund. The legal issue is that my contract is with Cocosa and it is their responsibility to refund me. They are not complying with their legal obligations.