BAD CUSTOMER SERVICE!!

I went to Katlehong Liquor Store at Katlehong Motse wa Lijane around 13:25 to buy voucher and the cashier on duty gave me bad customer service as she told me straight into my eyes that I should go to shoprite rather because they do not sell voucher.I told the lady that how is that possible because she had just sold the voucher to one of my friend and she quickly changed her statement and told me that even airtime is not coming out the system is offline.

Can the one up person for that shop do something about the service because customers cannot be told that a certain service is avaliable but when some of the customers go there are being told that the service is not available where as some customers are being offered the same service.

Can your staff please treat customers equally!