Missing too many updates causes an account to mess up (can't think how else to put it xD). Unfortunately this can't be fixed, so the best thing to do is to start a new account.

Might sound like a pain, but with so many updates all your parts will be obsolete anyway. On top of this leveling up now gives tokens which you would miss out on too. In the end you'll actually benefit from making a new account rather than trying to get your old one to work again.

Deleting an account isn't possible. However you can change your email in the Use Control Panel. After that you should be able to use the email you want for the new account.