I had locked my black jack phone by accident i didn't know what the security code was i tired every thing I even called my cellular provider and there where no help, So I found out how to format the phone which sets the features as if it was brand new phone and it worked after 5 hours of searching. what to do Samsung Blackjack and how to perform a hard reset on the device.  According to the user manual, to perform a manual hard reset, make sure the phone is powered off and then press the Up Navigation key and the Power key at the same time.

Be careful though, if you perform a manual Hard Reset, the storage and setting is also wiped clean.  I'm not sure if that means the Micro SD card in the device, but to be safe, I'd recommend ejecting the card prior to performing a hard reset.