MY PHONE IS LOCK AND I CANNOT UNLOCK IT. WHAT CAN I DO?

Check out this link below to download a PDF manual, software, and more for your phone. Just copy and paste into your browser.

http://www.samsung.com/us/consumer/mobile/mobile-phones/t-mobile-phones/SGH-T929ZKATMB/index.idx?pagetype=prd_detail&tab=support

Page 165 from your manual:
Reset Settings
From this menu you can reset your phone and sound settings to the default settings or perform a Master reset.
Reset settings
1. From Idle mode, touch Menu ➔ Settings ➔Reset settings ➔Reset settings.
2. Touch the check box next to each of the following that you want to reset
• All: Phone, Display, and Sound settings are returned to default values.
• Sound profiles: only sound settings are returned to default values.
• Display settings: only display settings are returned to default values.
• Phone settings: only phone settings are returned to default values.
3. Touch Reset.
Master reset
From this menu you can reset your phone and sound settings to the factory default settings.
1. From Idle mode, touch Menu ➔ Settings ➔ Reset settings.
2. Touch Master reset, enter your password, then select Yes to confirm.
The phone resets to the factory default settings automatically and when finished displays the Main menu.

Hope this helps, let me know if I can do anything else for you.
JimmyC