Re: Phone is "blocked" from T-Mobile - Anything I can do?
A good friend of mine recently went through something all too entirely similar and to T-Mobile's credit they actually ended up helping her out.
She purchased a Samsung Galaxy S5 off of Craigslist and it would not register on T-Mobile's network no matter what she did. After trying a Simple Mobile SIM and that working, she called T-Mobile to find out what was going on. After getting passed around she finally spoke with a Fraud Investigator who made no promises but asked that if she had any sort of receipt or email/emails showing a transaction he would see what he could do, especially because she wanted to start service with T-Mobile after being with VZW (since the day of Bell Atlantic Mobile).
She had multiple emails from the seller, plus she had printed out the Craigslist add (in case anything went wrong with the sale) and faxed all of them to the T-Mobile Fraud Investigator. A few days later he called her back that unfortunately she could not keep the device, but he was able to work it so that T-Mobile would send her a brand new Galaxy S5 at no cost to her. He ended up sending her a box and prepaid label to ship the "stolen" Galaxy S5 back to T-Mobile and IIRC the same day her brand new Galaxy S5 arrived from T-Mobile with instructions how to go about activating her account over the internet.
All in all it was painless and T-Mobile which had no reason to bring about a happy ending, actually ended up saving the day.
Dan