Temu Refused Refund After Return Of Package

On 3 November I ordered a bicycle from Temu, which was delivered on 6 November. Because I was traveling, the order was delivered to a Paketshop, but it was later returned and sent back to the seller on 18 November. Since then, Temu has refused to refund my money. Temu keeps insisting that the product was delivered to me despite all the evidence I have provided showing that I never received it.