Currys complaint: Refund for new purchase

I’ve ordered two new iphone 14 pro -128 GB, the payment was made via gift card coupon. The amount got debited from the gift card we got order placing receipt. Next day when we called customer support to know the details of our product, they said the order was cancelled due to invalid pin of gift card. And they will work on refund, been a week already. When I spoke to the support team yesterday again, they said the same thing not taking any action on the same. Telling me they don’t know where the money went, my side of issue is if we apply a gift card Or do any sort of payment to purchase a product currys take upfront payment before they generate a order. In my case they are saying order is cancelled due to invalid pin of a gift card, I believe if that is the case they won’t be able to proceed with the payment in the first place until I give right details, so either they don’t want to proceed with the refund or something other then that, when I asked for a escalation point of contact they team said they don’t have any contact for it.