Trade in never received, never got my old phone returned

Has anyone purchased a new iPhone on the promise of a trade in if you ship your old phone back in the packaging sent to you? I shipped the old phone to them in October, got an email confirming receipt and saying trade in would be processed. Two months later, another email stating that trade in had been cancelled either because I rejected their offer or I cancelled it and my phone would be returned to me.

I never got an offer and did not cancel. Now it’s been another month and I still haven’t received my phone. Essentially, they’ve stolen an iPhone 11Pro Max, in pristine condition, shipped to them in their packaging, as instructed, after I bought the 13 Pro Max on the promise of a $500 trade in. No response to my messages. WTF Apple?