traded in phone missing - Tmobile doesn't provided device recovery credit after THEY LOST the device

This is getting extremely frustrating.

I upgraded all of my 4 phone lines to new iphones back in December 2021.

For each phone I traded in an older iphone for which I was supposed to get a device recovery credit. However, for one of the phones I have still not received the promised  credit of $130 after 4+ months.

All phones were mailed to "Assurant" using the provided labels. The were all received there according to tracking. And for 3 phones they were "assessed" and the credit was applied to my account the same day they received it. Just this one phone shows "received" in T-Mobile's order history but does not show "assessed".

Over the past few months I have spent numerous hours on the phone and in online chat to resolve this. Every time I have to explain this again to a different person who then usually tries to convince me that I already got the credit because they see the credits for the other phones. 2 weeks ago I was finally able to get them to open an inquiry just to get a call today being told they cannot help me and I should contact Assurant. ¿Qué?

I gave that a try too but of course Assurant says this is handled by TMobile LOL

What a joke.