How do I get email from Facebook when I have never sign up for it and they had send me messages saying my account is blocked? My girlfriend is also on Facebook and uses my iPad, but we have separate email accounts. How did Facebook get my email address?
Some people are pretending/impersonating that they are from Facebook. I think they're hackers.
Just don't send them any personal information
This will, in all probability be a scam.
The message isn't from Facebook and the sender neither knows or cares whether you have an account or not. With 1 billion users (that's 1 in 7 of the world's population) they can send out these messages randomly and have a good chance of getting people who are on Facebook.
The message will have a link and/or attachment. If you open the attachment or visit the link you will be running some malware. Whether it installs or not will depend on how good your anti-virus software is.