You might have locked your phone trying too many pass code or pattern attempts.Only way you can get access to your device back easily is to hard reset your phone unless your phone’s mobile network was on before locking, if so you can get a temporary password in your mail.
Note:- Try this at your own risk and carefully.You may select another option by mistake and anything can happen to you device.
Just follow the below steps
I used the below steps to reset my Samsung Galaxy Grand
STEP #1 Switch off your Phone Using Power Button.
STEP #2 Press and Hold Volume-Up+Power+Home Button at the same time.
STEP #3 Wait for a while and you’ll see Android logo.Then release all buttons.
STEP #4 Touch screen won’t work while accessing this page.Use volume up/down to choose options.