Contact T-Mobile corporate office by phone. They will most certainly pull the account from collections if indeed they agreed to waive the termination fees.
I agree, contact them. You may have to move up the ladder a bit to be able to find someone who can actually do something.
Yes they did offered it and apparently it's nothing special, they do it for anyone moving anywhere in CONUS that is not covered by their network, if you are moving abroad or if you are in military and being deployed overseas.
Thank you for your advices, I will try discussing the issue with someone in upper management levels.