Lost trade-in phones

I signed up online for a trade-in promotion...trade in any phone and get an iphone14 for free.  I did this for 3 lines, sent 3 trade-in phones and T-Mobile claims they only received one of the phones.  All 3 phones were in the same box that was provided by T-Mobile, had multiple device slots provided in the box.  I packed all 3 phones, added some extra protection and the package was received successfully at T-Mobile.

However, only one of the phones was “scanned in” and they claim they don’t have the other 2 phones. No one at T-Mobile will take responsibility for the loss of the other 2 phones!! I have spent countless hours with customer service and on hold trying to remedy this situation.  Now I don’t get the promotion, I’m being charged every month for the new devices (all 3), and I can’t return the “free” phones because it’s outside the return window. 

Has anyone else had this problem?  The WORST experience ever with a phone carrier!!  I will be leaving T-Mobile immediately!!!