Customer is always right? Apparently not the case

I approached the women at the counter (Khanyishle) and requested MTN airtime. Paid for it and walked out only to realise that I had been given Cell C airtime. I went back in to the Fresh Stop store and made the cashier aware of her error. She was not at all understanding and simply told me that the error was mine for not making sure she had scanned the correct airtime. I asked for the manager who was level headed to his credit but was nonetheless of no help. He told me that there are no refunds on airtime and that he simply cannot do anything to assist. He took the part of his cashier and also told me that the mistake was on my part. I requested proof and questioned \should the customer not get the benefit of the doubt?". The cameras could not be accessed as visual proof of the incident and I was requested to come back another time. Returning to prove my point would be in vein as the manager would still not be able to remedy the situation.<br> <br> Please be vigilant when making purchases at garages and make sure that the cashiers do their jobs properly becasue it is clear that they is no way to remedy mistakes made on their part. Be prepared to count your loses should an error occur."""