Miscellaneous topics that do not fit into specific categories.
Canceling your Microsoft 365 subscription won’t stop this. What you’re seeing is almost certainly card data being used elsewhere, not abuse of your actual Microsoft account or subscription.
Fraudsters are testing stolen card numbers, and Microsoft is just one of many merchants they try. The fact that it keeps happening even after replacing the card strongly suggests that the card is being exposed repeatedly (saved in a compromised site/app, not necessarily Microsoft site.
I am afraid you would need to work with your bank to open an investigation, don't just simply change your card. Banks/credit card companies usually have options to guide you through situations like this.