Double charge, rude manager, rotten spinach

Today, on my weekly trip to the Food *****'s Market at Stoneridge centre in Edenvale, I realised after returning to my car that they had charged me twice for the food I had just bought. This apparently was due to a problem with the swiping machines at the paypoint. After returning to to the shop to point out the error, the cashier alerted the manager who said he'd "be a minute" and then continued, in front of me, to casually do mundane tasks like pushing trolleys around. Eventually, with absolute no sense of urgency he approached me and WITHOUT EVEN AS MUCH AS A GREETING OR A "what seems to be the problem, ma'am?" he just said "whats the amount?" and then proceeded to go to the office apparently to get "proof" that the money was not in their account. He returned and told me it's the bank's fault and perhaps the bank will reimburse me but that it was not his problem and that I should take it up with them. Now, I understand that sometimes there are technological issues, but my main issue is HOW this manager handled the situation. He was rude, dismissive and did not seem to care at all that while I, a customer at his establishment, was paying using machines in their establishment, got billed twice for the same thing. I at the very least, expected to be treated with a certain level of respect and decency and for the manager to perhaps be apologetic. What I did gain from the experience was that I should not shop there because I cannot trust the establishment or their paypoint machines or their management! And to top it off, I realised when I got home and opened the packet that the spinach was ROTTEN! Thank you, Food *****'s Market for making the choice of where to shop that much easier!