Is your Facebook account temporarily suspended? You can try resetting your Facebook password.
If it won't let you reset your password you can try looking through Facebook help topics.
According to Facebook you have to go through a security process to unsuspend your account.
If you think your Facebook account was suspended by mistake, contact information is available for Facebook personal. They can look into your account to see if it's not an issue with their security system.
You can email your situation to any of Facebook contact email addresses.
If you send an email to a disabled facebook email address, please follow those directions under "I think my account was disabled by mistake" section.