How to block fraudulent customer

Hello,

I have a customer who has been buying multiple gift cards from us, multiple days in a row. They only buy one gift card in an order, and they buy on different days; the amount varies, though.

We eventually realized this customer was likely using stolen gift cards, and so we canceled their orders and blocked them, but they have just made a new account.

Does anyone have any suggestions on a flow I can put together that would flag this behavior, not fulfill the gift card, then cancel the order, and send a notification to me?

Find something consistent across orders. Check that in a workflow and cancel the order if you see it.

Find some similar data, such as IP, shipping address, contact information, etc.