No cash back

I just went to checkers at goldfields mall on welkom... I purchased a bottle of cooldrink and wanted cash back of R340, the cashier told me he can't, i asked him why he said they are not supposed to... I asked to speak to the manager and a guy with the name of Tendai came to the till and told me the cashiers are all new and can't do cash back,i asked Tendai to show the cashier how to do cashback and he said he is not supposed to... What type of service is this? Is it possible that all cashiers can be new? What type of customer service is this? Are we as customers supposed to just eat these lies we been fed?