[mothered]

I do have record of all communication. They haven't outright said the refund is on it's way, but they keep saying "your issue should be resolved in xx hours" etc. The customer service keep forwarding the claim to the "specialists" and they keep denying the refund request.

Ridiculous to say the very least.

On what grounds are they denying the refund?

Incredibly frustrating. 

Here is what they wrote:
“Thank you for taking the time to provide us with more information regarding your request for order x. After further review, we have decided to uphold our original decision.”
Why was my appeal denied?
“We closed your claim because the tracking information for this order shows that the shipment was delivered. If you need assistance locating your shipment, we encourage you to contact Transportation Services.”

Some companies just don't care at all what you say and will just keep referring to the tracking, just like amazon are doing here.

How was the package delivered and accepted?

Also, were there any conditions on delivery such as a signature required?