Samsung S26+ not listed for Apple trade-in

I am looking to trade in my current device (Samsung S26+) to either the iphone 18 or the iphone Duo when preorder is available. I made the switch to android about a year ago and got this phone brand new at the time of the release. I just am not the biggest fan of android, and I want to switch back to apple. I went through the trade in process but the device isn't listed. what do I do?