In August 2013, I bought a T-mobile HTC One and I was able to get it unlocked fairly easily using htcimeiunlock.com
In December 2013, I had to send it in for repairs and it received it wiped from the factory. The IMEI number had changed so I used the same service again and it worked flawlessly.
Now in July 2014, I had to send it in for repairs, again wiped from the factory and the IMEI number is different. I tried using the service but then it failed to work for me. Could it be the algorithm has changed and T-mobile is cracking down on this type of thing? Or is my IMEI so brand new that there is no code for it yet and I have to wait a few weeks until someone generates one.
I am hoping someone knows the answer as I continue to pay for a non-Tmobile voice/data plan that I can't use =(