Hi,
I understand that someone is trying to use your account and using it in sending emails.
Possible that your account has been hijacked, we recommend you to safeguard your account to prevent this from re-occurring as your account may have
been accessed by someone somewhere to send unwanted emails from unknown or known contacts.
Kindly change again your account password and reconfigure your password reset information.
Click here
for steps on how to change your Microsoft account password and here
for steps on how to reconfigure your password reset information.
You may also check your account information as there may be an alternate email address that you do not recognize. The other alternate email address
will receive email notification every time you change your password and the hacker may change it again. If you do not recognize the alternate email address, you can remove it.
Also, please view the following articles to protect online privacy:
Protect your privacy on the Internet.
Your information on the Internet: What you need to know.
Take charge of your online reputation.
Check your password—is it strong?
Create strong passwords.
Please do not hesitate to post back if you need further assistance.
Thanks!