[ruonis55]

So I've now been denied my refund request twice.

Here is what the douche rep wrote:
"We are contacting you regarding your A-to-Z warranty claim on order xxx.
As noted above, we have again considered the warranty claim and the information you provided to us. We have concluded that our decision on this A-z warranty claim remains unchanged.
We ask for your understanding that it is not possible to reprocess your warranty claim even if you disagree with the decision. Please note that customer service cannot provide you with any further information in this regard."

I'm in contact with their customer service and they keep assuring me that the refund should go through, but it all leads back to this guy above it seems. How should I proceed here?

The package was left outside with no signature, although the seller is not amazon but it all goes through them.

How much was it?
Try and say it was damaged.
If that doesn't work return an empty envelope and file a dispute/chargeback and give the bank the Return authorization number and tracking number saying you returned it. It works trust me.

It was roughly 1500€. If I say it was damaged they will request it back.  The empty envelope doesn't seem likely to work, they would see the weight difference.

They won't, as far as I experienced. I recently did a Return FTID, in the DHL website there is no mention of what weight is the package, so didn't have trouble sending it and getting a refund. If you see that this chatting with reps don't go anywhere, you should do it or else you can say goodbye to your 1500 euro, or do a chargeback.