Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
If you log into this link on your Microsoft account, do you see two separate subscriptions listed, or just one subscription with the subscription expiry date extended?
https://account.microsoft.com/services/
If you do see two separate subscriptions, select the new subscription and click Manage, form there, you can cancel the new subscription, you should then be entitled to a pro-rata refund, and ensure you disable recurring billing on that subscription.
You can check your eligibility to a refund using the steps they provide on this link.