Here's few tips to help you get your wifi working:
Rooted android phone.
1. Download Market Unlocker (Google it, as you might not find the APK on Google play).
2. After download is complete, open it and give Root privileges.
3. On last tab, pick USA T Mobile, and wait until you see "Your mobile have changed to T Mobile successfully".
4. Make sure Wifi is off and reboot your device.
1. When you reboot your phone, make sure the wifi is off, or your wifi will freeze as usual.
2. after reboot or boot up, make sure not to enable wifi until you see your mobile signal working(Means the mobile
is not still searching for signal).
3. Market unlocker should change your mobile SIM Code every time you reboot (It will give a
notification). in case you are not sure if it worked, open market unlocker and pick USA T Mobile again.
4. Open Wifi and Violla.