None of this is your problem: you are not a merchant. What is wrong is the analysis of various people who think cash is cheaper and thus get mad at not getting

None of this is your problem: you are not a merchant. What is wrong is the analysis of various people who think cash is cheaper and thus get mad at not getting a cash discount. It is also wrong that a number of merchants are bad at accounting: they think that cash is cheaper by enough to be worth a discount - but this is not your problem either.