Hi i'm Rain First lets try a Soft Reset.
Remove battery ,wait 1 minute replace battery and boot Mobile device.
If this does not work you will need to do 1 of 2 things. Take the phone in and have them reset it.
The other option is a Hard Reset.
To perform a Hard Reset :
Then select Security
Click Master Reset
Then select yes
Type Default password 0000 4zeros
Phone will reboot after it has performed the Master Reset.
I hope this information has been helpful.