My cousins Minecraft account was stolen

Disclaimer: Due to this thread is posted in Spanish locale forum. But because you use English for this post, I will answer according to the language you use. If you need me to answer in Spanish, please feel free to let me know, I'll answer in the language you are comfortable with.  

Hello Dahian Mora,

Welcome to Microsoft Q&A forum

I can see that your cousins Minecraft account was taken over and the hacker changed the email and recovery info.

In this case, because this is just a Community Forum and we do not have access to your account and this request may require sensitive personal information. It is best to contact Microsoft Support chat using an account you still have access to and request assistance about your cousin hacked account issue.  

1. Open a website link - Contact - Microsoft Support 
2. In the box below "We're here to help", type Microsoft 365, click "Get Help", and then click "Contact Support" below. 
3. In this section, you will need to sign in to your Microsoft account. 
4. Select "Microsoft 365 and Office" under Products & Services, select "Technical Support" as the category, and click to confirm 
5. You can select " Chat with a support agent in your web browser " to access the chat window.