✔ 最佳答案
Inform Microsoft to help you.
You should first set up a backup email address,
and set your backup email address as the primary backup.
Delete the backup address that the hacker has set.
Then,
change your password
You can always delete your account,
by log in the option menu in the account
and click 'Delete my account'
But you should bare in mind that the owner of the backup email address can reactivate the deleted account at any time, so changing the backup email address is the first priority.
If you can't change the backup email address, report to microsoft that your account has been hacked.
You better find someone you trust and has certain level of computer knowledge to help you on this issue, this is a complicated case.