Cancel button is the worst idea in the world. Not only are they confusing to users, they lower conversion. What's the good in that? I'm going to say the user is smart enough to close the browser window.
It is generally expected that you have a cancel option (to cancel the transaction). Every online system I've used for payments has a clear "cancel transaction" button.
It is generally expected that you have a cancel option (to cancel the transaction). Every online system I've used for payments has a clear "cancel transaction" button.