charged with no visable subscriptions

Log in to all of your Microsoft accounts and check if you can see the charges there.

https://account.microsoft.com/services/microsoft365/billing

If not, have you asked a family member if they may have used your card in the past?

You can refer to this article: 'How to investigate a billing charge from Microsoft.'

https://support.microsoft.com/account-billing/how-to-investigate-a-billing-charge-from-microsoft-398c5328-364c-d5e4-ea8f-f5ad60562a93

If you can’t find the source of the charge, it’s possible that your credit card has been compromised. In this case, you should contact your bank immediately to open a dispute ticket, request an investigation, and, if necessary, have your card blocked and replaced to prevent further unauthorized charges.