@Redsquiral: Rajab 12 is an event in the Islamic calendar, although I'm not too sure why this would suddenly be visible on your lock screen. If you enter your passcode incorrectly a few times, can you see a 'Forgot passcode' prompt, either above or below the keypad? If so, tap on the prompt and follow the on-screen instructions to reset your passcode.
If the issue persists, and if you have proof of purchase, then you can arrange for an authorised Samsung engineer to unlock the device for you. In this instance, please had to samsung.com > Scroll to the bottom of the page > Contact us, and reach out via your preferred contact method for further support.
