Scammed out of $2200 Trade in Credit

I moved to a new place and got Xfinity Internet and they told me I will get a free line for a year and $1100 credit for each of my two iphone 13 pro max if I trade them in for iphoner. They kept calling me to get me to switch to xfinity and I finally decided to do it. But before I switched I asked them if they can ship one of the new phones a month late in December since I was going to be out of country and could not send my old phone back until December and they said I absolutely can and they will let the carrier know and they will take care of it. I agreed to switch and they did all the process, and placed the order on Oct 10th 2025. I received both the new phones on Oct 26th even though I specifically asked them to send me one in December. So I called the customer service and they transferred me to some backend team and they assured that me since I was promised that I can send the trade in phone in December, I can keep both the new phones and send one of the old ones in December and I will start getting my credits for that as soon as they get the phone back. So, I sent them one Iphone 13 Pro Max in November and I got and email that my Trade in was complete on Nov 12th, which was within the 21 days. And I sent them the second phone in December like I promised, but they sent the second phone back to me. So I called them to see what the issue was, the agent confirmed that they received the phone and is going to apply the credit for the first phone and puts me on hold and after keeping me on hold for like 10-15 min he hung up on me. I called again and same thing, hung up on me. This happened 4-5 times and has been hands down the worst company I have ever dealt with. I never received a callback from any of the agents even though I asked them to call me back if it gets disconnected. I was a very happy T Mobile customer for 8 years and have never seen such scamming tactics and fake promises from any customer service. If they could not do it they could have just simply said no and I would not have switched. Agents lied to me multiple times and made promises that were not met. I am out of options on what to do since $2200 is in no way a small amount for me and it is extremely frustrating. They have all the notes from my previous conversations with the agents and still are not willing to do the right thing. If this does not get resolved here, I am going to file an FCC complaint and get legal help.