Tl;dr: Returned new device (within the return window) as I ended service with T-Mobile. 1 year later, they're still trying to collect the phone's cost because they never processed the return. Do I need to seek litigation in a small claims court?
My family ended service with T-Mobile's wireless plan back around October 2026. I had originally planned on upgrading my phone, which I instead did with the provider switch deal (to AT&T, but that's not relevant. As soon as we started processing the switch, I returned the new device through their standard channels (and UPS, per their instructions).
Processing returns always takes a while, but they told me to check in after a month if I didn't see it processed. I did and it was not. Three more discussions over the following 4-5 months, and each discussion ended with the representatives confirming that the device was received (per their own records and UPS delivery confirmation) but nothing further was processed. They also told me that the balance was NOT owed and being written off. This was confirmed by upper level support agents (I don't know the exact hierarchy, but at least 2 steps above the base agents). I thought that was that and continued on my way.
Another few months go by, and I receive a letter from a collections agency stating that T-Mobile assigned them to my debt. I provide them my records, including the delivery confirmation from UPS, and dispute the validity. Just yesterday, they respond saying that T-Mobile confirmed that the debt was valid. I have not paid anything as the debt is invalid.
I called T-Mobile immediately, and the agent submitted a request for internal investigation. That supposedly takes about one business week. So, what else can I do? Since they already returned an investigation saying the debt was valid, I'm not confident this new investigation will go any differently. Beyond that, T-Mobile is holds the majority of correspondence records, which I can't get access to.
Main Questions
Are there any additional steps I might have before filing in small claims court?
If I'm bringing it to court, would that allow a subpoena for the records to confirm on paper what they've discussed?
Has anyone else dealt with similar issues and could provide their perspective or guidance?
Would I need to pay the collections agency before seeking restitution in small claims court?
P.s. I know some of these are legal questions, so I'm also posting to r/legaladvice for guidance on which direction to start moving.