I want to add a few details as to why this didn't seem as out of the norm to me as it should. I'm used to paying out portions of a project to other contractors, usually design partners. I do it to make sure my contractor partners get the payments they need so that it doesn't hold up the project. There are other details of the story that I left out, specifically regarding how I would caught this a LOT faster had it not been for how QuickBooks Payments does things, but I'm not out to vilify them. I still use them, and I still take cards as payment.

Still, none of that is really the point. The biggest thing I'd like people to focus on is how little power merchants have regarding chargebacks, especially when a third-party processor is involved. Now that chip readers are becoming the standard, more and more liability is being shifted from the massive card companys to the small merchants, in part because of what happened with Home Depot and Target recently.

I've learned a very hard lesson in a very hard way. I've shared my worst-case scenario in the hopes that it helps others. Isn't that what we're supposed to be about in the WordPress community?