I forgot the security questions

Read this document (and links inside it) about using security questions: Change your Apple ID security questions - Apple Support

Several years age Apple transitioned to using to two factor authentication instead of security questions. If you are still using security questions and have problems with them that are not addressed in that document then your only recourse may be to see if at this stage you can change to two factor authentication as outlined in this article --> Two-factor authentication for Apple ID - Apple Support Then follow the instructions in the section "Turn on two-factor authentication for your Apple ID"

If you cannot sign up for two factor authentication, contact Apple for help with Apple ID account security using the information in this document --> Contact Apple for help with Apple ID account security - 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