Hi rahisha. If you forget your unlock pattern, the only way to reset it is to log-in to your Google account. But since you forgot your email and password, there's no other way to access your phone other than doing a hard reset.
To do a hard reset:
1. Turn OFF the device. If Samsung Galaxy 550 is frozen, pull out the battery and reinsert it.
2. Press and hold the Volume Down button and in the same time press the Power button in order to power on the device.
3. Select Clear Storage using Volume Down to navigate and Power button for selection.
4. Then, you have to confirm that you want to hard reset your device. Press Volume Up for yes or Volume Down for no. Now the Hard Reset process will begin. When the Hard Reset process is finished, the device will reboot! source