MetroPCS Unlock Codes?

Help me, I made a mistake and put my phone in NAM2 setting. It locks your phone and you need a default code to unlock it. It is not my last 4 digits and its not 0000, 9999, 1234, and so on. I have tried everything. If anyone knows how to unlock it, please help me. By the way, its a Samsung SCH-a870. Please help