Hey there! Nice to meet you!
You mentioned, "someone changed the verification email again." This indicates that your Microsoft account was compromised. The hacker was able to remove the account's primary email address/security info and replace it with their own email address.
The only way to recover a hacked account is through the official Microsoft troubleshooter guide:
https://support.microsoft.com/account-billing/how-to-recover-a-hacked-or-compromised-microsoft-account-24ca907d-bcdf-a44b-4656-47f0cd89c245
If the account recovery web form doesn't work, and since the security info has been replaced by the hacker, I'm afraid there is no other working method to recover the Microsoft account, and Microsoft Support cannot help either.
In case the account recovery request is successful, you will need to update your account's security info on account.microsoft.com > Security > Manage how I sign in > then add your verification method (email or phone number)
Once you're done, you will need to wait for the 30-day restriction state to complete adding the verification method; but, if the hacker has their email or phone number already linked to your account, having them in full control over your account, they can simply cancel your security info change request.
If this happens, you will need to try requesting again, and hopefully, the hacker will not notice.
Unfortunately, it is also not possible to bypass the 30-day restriction state.
However, if the 30-day restriction state is complete, you will be able to remove the hacker's security info email/phone number from your account using your newly added security info.
Thank you for your understanding! Please let me know if you need anything else.
Best regards,
Darhyl