Facebook has how many users? If .5% of the users were having the same issue as you, and it took 20 minutes for an issue to be fixed, and you were last in line; How long would it take to get to your issue?
Some examples include:
• Using a fake name or not using your full real name.
• Creating two personal accounts.
• Impersonating someone
• Continuing behaviour that's not allowed on Facebook by violating the Community Standards
If you think that your account was disabled by mistake, you can appeal Facebook's decision, in your appeal, you must prove that Facebook made a mistake. Saying that you are sorry, that you did not know about the rules or that you will not do it again will get your appeal rejected.