I was just scammed by AT&T!!

I've been a customer of AT&T since 2010, I've always paid my bill on time and have had several upgrades over the years without any issues. In September I got an offer to trade in my wife's and my iPhone 12 pro's for $1000 a piece. Normally, I would sell our old Iphones for several hundreds of dollars on eBay and pay off the new phones over time, but this promotion was to good to pass up, so I signed up for it on 9/23/24. So I sent in our trade ins with the box and shipping label that they provided. After waiting over a month for credit, I decided to call AT&T to see what the hold up was since I just got a bill for close to $300 dollars. The first agent I spoke to said that the plan I have was not eligible for the $1000 per phone trade in. I told him I changed my plan on 9/23/24 and have the emails from them to prove it, he just kept repeating that my plan isn't eligible for the $1000 trade in and transferred me to his manager. His manager repeated the same thing and told me that I would only get under $200 for my trade in. Why would I ever agree to that when I could have sold them on eBay for much more?! they were in perfect condition! I told him that if you’re not going to honor our agreement then send me back my phones and I’ll return the iPhone 16’s and we’ll call it a day, he then informs me that they can’t do that since been a month and a half. I KNOW I specifically signed up for the $1000 trade in offer, now AT&T are not honoring the agreement, this totally feels like a bait and switch. They have my old phones and now they’re not giving me the credit on them, this all seems illegal. What recourse do I have? Has this happened to anyone else?