T-mobile refusing to give me my credits from a promotion I qualified for

I also was misled and cheated by T-mobile's promotion. I traded my iPhone 11 for the the iPhone 13. I've had to call  T-Mobile numerous times since I got the plan which was an August 2022. One of rep entered the wrong information for the phone I traded in. When I called to point out the mistake they said it was a generic text it didn't matter what phone you traded in it will be the same information for everyone. When I called again to dispute the amount they valued my phone nobody said anything about my find my phone app left on the phone. They told me my rebate would be applied to the bill.
When I called to follow up on the rebate because I noticed it wasn't applied to my bill. I spoke to a rep and they tell me I am not getting anything bc I didn't turn off find my phone app on the phone I traded in. I told them I did because those were the instructions that were given to me and told them why wasn't this mentioned sooner the many times I called. I said check your notes I've called many times for this issue. I was gaslighted even by the supposedly a manager. I told them to send my phone back and they said they won't. Why would they need my phone is supposedly it cant be used. 

I called Apple and they told me that if I didn't turn of the find my phone app on iPhone 11 it would show on the iCloud and on the find my phone app. It doesn't show on either. My phone was stolen by T-mobile.