Teach Portia from pep home tsakane mall to speak to customer's with manners

I went to Pep home to find voucher I asked which one they have and I asked for 50rand voucher then she "Portia " cashier gave me 100 rand voucher and I said to her I wanted 50rand voucher she rep**** to me with attitude they don't sell 50rand voucher and I shouldn't buy at pep home anymore she doesn't want me in her store anymore I work at trail store too but this customer services is very bad I got very angry and yes i promise will never set my feet at pep home ever again