Microsoft hijacked my account. How do I get it back?

I received two e-mails recently telling me that my account information had been updated. One of the e-mails listed my mother's e-mail address and phone number as the new information and my information as the information to be deleted. I called my mother. She said that she had been having trouble accessing her e-mail and had called an automated number for help. They sent her an automated code. She input the code and now she has access to her account. Shortly thereafter is when I received the aforementioned e-mails telling me that my microsoft account information had been deleted and hers is now in it's place. I have searched the internet for three days to find a solution or a phone number to speak to a live person. Finally, this morning, I got in contact with a live person to ask for help. She informed me that she could not help me and directed me to this website. I asked her to stay on the line with me while I navigated the website. She then hung up on me.