To receive a refund, you will need to cancel the subscription first.
For refund eligibility and the steps to cancel the subscription, check the instructions here: https://support.microsoft.com/account-billing/how-to-get-a-refund-on-a-microsoft-subscription-67dca30b-b323-44d5-acc2-e02f9902c472
If it didn’t work or you want further help, for your security and privacy, I recommend contacting Microsoft Billing Support directly, as this request involves personal or sensitive information that should not be shared in a public forum.
Click this link: https://support.microsoft.com/contactus/
Sign in to your Microsoft account.
Select Microsoft 365 > Click 'Get home support'.
Type "Chat with an agent" from the text field and press Enter.
Click "Contact support" at the bottom.
Select the product you need help with.
Follow the prompts to connect with a live agent.
Customer service phone numbers: https://support.microsoft.com/topic/customer-service-phone-numbers-c0389ade-5640-e588-8b0e-28de8afeb3f2
To access the full range of support options, including chat, please contact them during business hours which are Monday to Friday from 9 AM to 5 PM local time.