[mothered]

They asked me if I could retrieve the device, even though I told them it was in a large dumpster

Tell them you've retrieved It.

Samsung told me that they had to evaluate the device before given a replacement and they would send a special box with FedEx to ship it.

Given they're arranging the return with the said box, they'd be responsible for loss of goods during shipment, so box them.

If you're not comfortable with the above approach, request your claim be escalated.