Another way but not a hack - is what I call (double tapping) . I had this happen a number of times.

At a store you swipe your card but the cashier says it did not go through , please swipe again . Later you find out you been double charged . SO now when ever I have to double swipe I check my account the same day.

On line bill paying - snafu.
I pay about 300 bucks with on line payment , I then get an email confirmation . 3 days later I check my account only to find I was double tapped - I called the bank they said to (late) they paid the bills , wtf ?