not receiving verification code emails since migration to yahoo

This is a follow up to a prior discussion:

Not receiving verification code emails new Yahoo mail | Cox Community

I called yahoo support, and they refused to acknowledge that this problem exists and refuse to report this issue to the support team for yahoo mail.

Compounding this issue is a recent change made by Facebook if using incognito mode (Chrome) or inprivate mode (Edge), that will sent a verification code to the email address for the Facebook account before a person can log in. In my case, I have an old account that only has the single cox.net email, and no alternative means for verification, and Facebook doesn't provide support or any means to change the email address without being able to send a verification email to the now broken cox.net email address, which no longer works due to the migration to yahoo mail sever.

Repeating my post from the prior discussion, reddit is an example of the problem. Since I'm receiving normal emails from reddit, I tried to do a password reset, which is similar to a verification email and that failed, but I continue to receive normal emails from reddit.

I'm hoping someone at cox cable can report this problem to yahoo to see if they can resolve the issue.