nokia lumia 635 wont bring up plave fir me to put in unlock code

[Windows Central Question]

I bought a nokia lumia 635 and apparently the person had stole it and it hasnt been scanned i got the unlock code but when i put in unregestered sim from tmobile it wont bring up a place to put in the code can someone please tell me what to do?? My phone is a boost with sprint sim thanks!! < personal information removed by moderator >