I would like to cancel the subscription and request a refund, as the payment was made unintentionally.

Disclaimer: Due to this thread is posted in Russian 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 Russian, please feel free to let me know, I'll answer in the language you are comfortable with. 

Hello Куандыкова Асель,

Thank you for reaching out to Microsoft Q&A forum

I understand that you wish to request for a refund.

Please refer to this site for instruction on how to refund and check for refund eligibility:

https://support.microsoft.com/en-us/account-billing/how-to-get-a-refund-on-a-microsoft-subscription-67dca30b-b323-44d5-acc2-e02f9902c472
If you need further assistance about your refund, you can also contact Microsoft support, here is how to it:

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 "Manage my Subscription" 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.