you must learn basic hacking techniques first to hack any website then you can learn from video tutorials.
Sounds a little weak. I can access all my friends outside of Facebook. I have their phone numbers and email addresses. In almost any situation you need backup and alternative methods. You can't (totally) depend on Facebook. Also, the work hack might something you really don't want to do since in many cases it is totally illegal. Lots of good ideas in other threads. Facebook support sounds like the best option. You might want to research/discover why it happened. Bad/wrong user information, proxy servers, etc.