I don't know what Amazon actually does, but what I think of as normal is the customer calls the help desk and they reverse the charge. This seems simpler than w

I don't know what Amazon actually does, but what I think of as normal is the customer calls the help desk and they reverse the charge. This seems simpler than worrying about how to code algorithms that will deal with all possibilities. People make mistakes with transferring money in the millions of dollars all the time, and it's not uncommon for people to be just like "oops, back that out". It's obviously going to be in the news when that doesn't happen though.