Apple got a different phone than the one I sent for trade in

What a mess. I had a Samsung S22 Ultra. Traded in for iphone 15 Pro max, via carrier deal. Got the new phone, and put the s22 in the trade in box and sent back. a few days later, i get an email that my trade in was not what I sent, they said I sent a Google Pixel 4, and is worth $20 (my s22 was worth 325). I call , give them serial #'s, etc--they said they will investigate. They finally call back and say that the investigation shows i sent a pixel and case is closed and I need to reject the trade in to get it back. I reject it and today, I get it, and its a very old iPhone!!! No even the pixel. I call..ask for a manager. they are useless and say their hands are tied. I gave them the serial off the crappy iPhone and she says its not in their system--

ANY HELP is appreciated!!! thank you

[Re-Titled by Moderator]