If you want to cancel your Apple ID account, you can deactivate it or delete it.
Apple ID - How to deactivate your Apple ID account. *
All purchases made using an Apple ID are tied to the ID. Delete the ID and you will need to download them using your new ID. Once your Apple ID is deleted, you can't use the email address that you used with it to create a new Apple ID. In addition, you can't use that email address with another existing Apple ID except as a rescue email. Also, if your primary Apple ID email address is with a Custom Email Domain, it can never be reused to create an Apple ID after your Apple ID is deleted, even if the domain ownership changes.. Make sure that you sign out of all your devices to avoid issues with apps that use your Apple ID account or iCloud. After your account is deleted, you can't sign out of iCloud or turn off Find My iPhone Activation Lock on your devices. If you forget to sign out, you might not be able to use your device when your account is deleted.
How to delete your Apple ID account. *
Apple ID – How to Delete. -
Delete Apple ID (new). -
What to do after you change your Apple ID or password - Apple Support -
For the security questions, if you are being told there isn't enough information to reset them, contact Apple ID Support.
If you don't know the answers, if the steps in the article below don’t work, contact Apple ID Support, although based on multiple posts I have read, they will not help you recover the answers to your security questions.
Apple ID - If you forgot the answers to your Apple ID security questions. *
From the article below.
Without proof of your identity via security questions and other carefully selected criteria, Apple Support can't help you reset a password or perform any other actions on your account. These policies are audited and reviewed on a regular basis.
Security and your Apple ID. *
Apple ID - Official Apple Support. -
Contact Apple for help with Apple ID account security - Apple Support. * (Link doesn't always load)
Get Support - Work through the screens to get a chat option.
Apple Support schedule phone call. -
Apple on Twitter
Messages chat with Apple