Poor service

Yesterday I went to do shopping at mall of Africa between 11 and 12 am. I was using voucher and cash, my voucher couldn't load, the cashier(Nthabiseng) called frontline controller(Patricia) for assistant, I had to look for the message, she then whispered to the cashier (Nthabiseng) and looked away, the cashier laughed. Well I told Nthabiseng that I'm aware on what Patricia has done and I'm going to report them to head office. The voucher declined again and Patricia went to front desk and I followed her, she started complaining about south Africa and the vouchers, what are they benefiting from the vouchers. I'm always shopping at mall of Africa checkers and is the 1st time experience such bad service. Patricia seems to be judgmental and disrespectful.