Miscellaneous topics that do not fit into specific categories.
Hi. I'm Brian and I'll try to help.
Whether or not you closed the charter.net address is immaterial if you used that address to create a Microsoft account. The address is the username of the account and while it needed to exist when you created the account, once that was complete, the account on Charter doesn't need to exist any more. There is still a Microsoft account that exists that uses the Charter address as the username. You need to log back into that account at https://account.microsoft.com/services using that address as the username and whatever password you established at that time for the account and cancel the service. The password you used for the Microsoft account does not have to match what you used for the Charter account because they're completely separate accounts. Normally, if you haven't used the Microsoft account for two years or more, Microsoft closes the account automatically but because there's a subscription associated with the account, that account won't every be closed as long as payments can be withdrawn from the credit card you added to the account.
Perhaps you could contact Microsoft directly at https://support.microsoft.com/contactus and select the Microsoft 365 link. You should be able to start a chat with an agent. I'll warn you, though, you may be dissatisfied with that experience and may need to cancel the card and protest the charge through the card issuer.