If you're past due to return your defective phone, you probably owe Samsung some form of money. Make sure you're not returning a phone when you've paid for two.
As for unlocking, that's horrible, but unfortunately the world we live in. T-Mobile doesn't have it in their IMEI database, so they can't unlock it. If they do get the IMEI, there's no guarantee they'll provide the unlock because of the Unlock policies: Unlock your mobile wireless device
The only suggestion I have is to contact T-Force via Social Media. They will do what they can to hopefully get you an unlock code and squared away. The only other option is to purchase an unlock code from some third party (we do not have any suggestions for them).
Several more phonecalls to T-Mobile over the last week;
Getting told that my account is in collections (verified to be untrue) was the highlight. They will do anything to get you off the phone. Of course not mentioning the reps that put you on hold for "2-3 minutes" while checking their system and finally hanging up on the call.
One of the reps told me that the first unlock was a SIM unlock, not a device unlock, so they submitted another unlock request. Received the email earlier today stating that I can unlock my phone. Still not able to unlock, clearing the memory for the Device Unlock app, inserting 3rd party SIM, and still receiving the "Unlock failed: Device ineligible for unlock" error.
Staying pleasant on the phone with every rep that I am dealing with, but it's getting more difficult with each call...