I forgot my security questions

Try using Apple's iForgot service. If you can't reset the security questions through it, you need to contact Apple's Account Security team. To reach them, clickhereand pick a method; if that page doesn't list one for your country or you're unable to call, fill out and submitthis form.

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https://getsupport.apple.com/

Click on "See all products and services", should be a blue link at the bottom. Should go to a new page after clicking, click on "Apple ID", then "Forgot Security Questions".

You can choose what support you need on the page that shows up.

See: Contact Apple for help with Apple ID account security - Apple Support

You will need to use the Apple support over a phone call to get them reset.