Trade in refund

What you get depends on how you traded in the device.

You only get credit to your credit card if you do the trade in during the purchase of a new device and used your credit card to par for the new device.

If you traded in on its own without buying anything you get a gift card.

So you made the trade-in during the purchase of a new device? Was it shown at checkout?

Did you send in the trade-in item in the trade-in time frame?