I would suggest you reset your password first then if you want to totally delete the account you have to fill in a form according to this.
Should none of that work there is the little cog like icon top rh corner of FB page, click on that and then "report a problem" tell them you want to delete the account and see if they answer you (don't hold your breath though".
How do I permanently delete my account?
If you deactivate your account, your timeline disappears from the Facebook service immediately. People on Facebook won't be able to search for you, though some info, like messages you sent, may still be visible to others. We also save your timeline information (ex: friends, photos, interests, etc.) in case you want to come back.
If you don't think you'll use Facebook again, you can request to have your account permanently deleted. Please keep in mind that you won't be able to reactivate your account or retrieve anything you've added. Before you do this, you may want to download a copy of your info from Facebook. Then, if you'd like your accountpermanently deleted with no option for recovery, log into your account and fill out this form.
If you can't log in to your account, you'll need to reset your password first. To do this, go to www dot facebook dot com and click the Forgot your password? link below the password field. Once you’ve followed the instructions to reset your password and can log into your account, you can deactivate or delete your account using the steps outlined above.
