Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
If you have purchased a second subscription, you can pre-load your subscription up to 5 years in advance, if you add the second subscription to your account, you should then have 24 months on your subscription instead of 12 months.
If you want to cancel the second subscription, you can use the steps on this link to check your eligibility for a refund and cancel the second subscription.