Young Wizard, we have put safeguards in place so that this doesn't happen.
In order to delete your Wizard, you had to: - select the Wizard to have it standing up at the front of the screen - click DELETE - then you were shown a screen with the Wizard's Name to confirm that's the one you wanted to delete, - typed a long word into a field and clicked DELETE.
If someone else logged in to your account and deleted the Wizard, you need to change your password. Remember, exchange of usernames or passwords is a ban-able offense.
If you managed to make it through all those steps and still deleted the character 'accidentally', the sooner you contact Mr Lincoln at support@wizard101 with a polite request to restore the character, the better chance you have of actually getting that character back.