They way it works I don't receive a charge like you do with visa, the merchant presents a code, you scan it when your bank app and then the bank app asks if you want to send # of money to [merchant name], if you don't want to pay it then you don't approve the transfer in your app on your phone.
However after the fact there's less options, I've never gone through
However after the fact there's less options, I've never gone through