"We do not have sufficient information to reset your security questions."

See If you forgot the answers to your Apple ID security questions https://support.apple.com/en-us/HT201485

Apple has notified you that you are unable to answer your security questions successfully. See Security and your Apple ID https://support.apple.com/en-us/HT201303

This document says “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.”

Thus, given Apple's notification, we can do nothing to help you, except to mention that Apple support might help you if you have an extenuating circumstance (e.g., you have the receipt for your purchase of a pertinent device with its serial number on it or a court order instructing Apple to assist in the provision of access to a decedent’s information from the deceased person's accounts). See How to request access to a deceased family member's Apple accounts https://support.apple.com/en-us/HT208510. if you want to contact Apple support to discuss an extenuating circumstance, even one not just mentioned, see these support options:

Get a call from Apple support to help solve your problem using this link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362

Apple ID Support https://support.apple.com/apple-id

Apple ID account security for country-specific and region-specific help https://support.apple.com/en-us/HT204169

Get Support: We’re here to help https://getsupport.apple.com/. Go through the options to find the best support option.