Things you will need for active accounts:
1. MEID of the device
2. Account PIN Code
3. Phone Number
Things you need for INACTIVE Accounts or Phone:
1. MEID of the Device
IMPORTANT! IF THE PHONE HAS NOT BEEN ACTIVATED ON A SPRINT ACCOUNT BEFORE THE UNLOCK WILL NOT WORK!
ALSO IF THE DEVICE IS FINANCED OR THE DEVICE HAS BEEN REPORTED LOST OR STOLEN (BAD) ESN THE UNLOCK WILL NOT WORK!
Steps to be taken
1. Call 1-855-899-7924 (Sprint U.S. Tech Support)
2. Ask for a Domestic Sim Unlock
3. Tell the operator to submit a "click-it ticket" for devices that are not BAD OR FINANCED ESN. The error code is 2009
4. Make sure they give you the ticket number and put it in a safe place!
5. Wait about 48 hours and call back to the tech support number listed above.
6. Ask the tech to do the Unlock again.
7. Try and put a T-Mobile sim card in it.
In Step 2 above the operator will try to process the unlock right away, but it will fail EVEN if the operator says "Successful" through their unlock submission.
I unlocked an iPhone 5s and it is working on T-Mobile as seen in my pictures. I hope this helps everyone that has been frustrated with Sprint's tech support trying to get their devices unlocked. If you have questions or corrections please let me know i'll fix it.