Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Use the website listed in the box to install the new product key. I think you will have to enter your email address and after to successfully enter the product key, you will be able to see the new subscription in your account under Orders. You still won’t be able to access Services and Subscriptions, and you might receive an email saying your Microsoft365 expired (I did), but you should still be able to access all of the apps included in the subscription.