Hello,
Thank you for posting in the Microsoft community forum.
We understand your concern. May I know if an unauthorized transaction refers to a Microsoft product or service?
You can verify for yourself whether there are any automatic renewal or additional purchase options in the subscription service. If so, consider turning off these options to prevent unauthorized transactions.
Please note that Microsoft does not proactively ask you to provide any sensitive personal information, such as credit card numbers, passwords, etc. If you suspect your information has been misused and you've contacted your bank, follow up to make sure they take appropriate steps to deal with your situation, such as freezing the card.
In addition, we recommend that you update passwords for all Microsoft accounts associated with this credit card and enable two-step verification (2FA) for added security.
How to use two-step verification with your Microsoft account - Microsoft Support
Best regards
Jacen