Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
To better understand your situation, could you please provide a little more information:
- When the subscription is charged, do you receive any Microsoft billing receipt or invoice by email? Billing receipts can often indicate which account was used for the purchase.
- If yes, which email domain receives it (for example: outlook.com, gmail.com, yahoo.com, or a business domain)?
- Does the receipt show any part of the Microsoft account associated with the subscription?
- Do you know the exact subscription name (for example, Microsoft 365 Personal, Microsoft 365 Family, Microsoft 365 Basic, etc.) and the amount being charged? The subscription type and charge amount can help determine how the subscription was obtained.
- You mentioned Microsoft created a long account name when you subscribed. Do you still see any portion of that account name, username, or domain in any previous Microsoft emails, invoices, or subscription-related communications? Any portion of the account name or domain may provide clues about the type of account involved.
- Approximately when was the last time you were able to successfully access the account that is now requesting Microsoft Authenticator verification? It may help assess what account recovery options might be available.
For your privacy and security, please do not post your full email address, payment details, or any other personal information publicly.
I look forward to your response.