Thanks.
If you have reason to believe your Apple Account has in fact been compromised, then the Apple Support document If you think your Apple Account has been compromised - Apple Support explains how to proceed.
However, I am not entirely convinced your Apple Account has in fact been hijacked. If you can log in to this website, then you are definitely using authentic Apple Account credentials. Using those same credentials, verify your personal information is correct by logging in to your Apple Account, here: https://account.apple.com/
If you can successfully do that, then consider the following possibilities.
- The emails are being sent to you by accident,
- The emails are being sent to you by someone whose Apple Account may have been compromised, and is mistakenly using your Apple Account credentials in an effort to regain access to their Apple Account.
If you believe those explanations are applicable then all you can (or should) do is ignore them. Send them to Junk, and they will eventually cease.
A complicating factor is that Apple has not used "security questions" in years. They are no longer useful and are effectively obsolete. However, Apple does maintain this archived Support document that may be worth reviewing: If you forgot the answers to your Apple ID security questions - Apple Support. The fact it is archived means it may not be helpful to you. For example, you can provide correct answers, and it still may not allow you to reset anything.
This old Discussion may be worth reading, but be advised it is long, with an abundance of conflicting and confusing factors:
Someone trying to hack my Apple password using security questions - Apple Community
It does not come to any kind of conclusion but I suspect your circumstances may be similar.
Another potentially relevant Discussion: Unable to Reset Apple Account Security Questions - Apple Community