Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
If you have paid for Microsoft 365 Premium twice, that has most likely pre-loaded your subscription for two years, log into your Microsoft account on this link and check the expiry date on your Microsoft subscription, does that indicate you have two years remaining on your subscription.
https://account.microsoft.com/services/
If that is what is indicated for your subscription, do not try to cancel the subscription, you may loose both subscriptions, this forum is just a user to user forum, no-one here has any account access, you will need to contact Microsoft Support directly, try using this method to contact their support.
Go to this link: https://support.microsoft.com/contactus
Select Microsoft 365
Click 'Get Home Support'.
In the box provided, type billing.
Press Enter, then on the next page, scroll down and click 'Sign in to Contact Support'.
Navigate to Microsoft 365 and Office - Manage my Subscription.
Select the 'Chat with support agent in web browser' option