I am not an American, and the American ways of transferring money are mysterious to me. When I want to send money from point A to point B, I log into a web page, fill in the required data, confirm the data, and in a day or two the money is there. If I understand it correctly, the American way to do this is to personally go to the bank, take a paper form, write the data on the paper, deliver the paper to the target, and the target must take the paper to their bank.

It was a huge surprise to learn this, because I automatically assumed that the American ways of dealing with money must be more advanced and more convenient, just because of having more experience with internet and capitalism in general. But now I guess that the American system is simply a victim of its own inertia: these methods were invented and became a norm before the internet, and now people are resistent to the change, because no one wants to experiment with the new methods when their own money is involved.

Still, I agree that the second transaction should be cancellable after the first transaction was cancelled. Not sure what is the trick here. Maybe the scammer wants the part of their money returned using a different method (one that does not allow cancelling, or has shorter deadlines). Maybe the plan is that most people will not notice the cancelling of the first transaction, or be busy enough that they miss the deadline for cancelling the second one. Maybe there is some psychological trick preventing the victim from cancelling. Really, I don't know (and not being familiar with the American system, even if I read an explanation, there is a chance I would misunderstand it).