Incompetence & unprofessional = unhappy customer

I had to rush to the shops yesterday. Was greeted friendly by the cashier (17:42 on 21/03/15 - cashier 3 WC35) - credit for that. I had a voucher for R50 which she put through as 50c. I showed her the mistake and she buzzed the supervisor - who did not show up. I waited about 2 minutes and offered to fetch her to which the cashier almost fainted (maybe afraid of the woman?). She kept on buzzing - 5 min LATER the supervisor appeared! Took off an item which the cashier rang up twice and walked away. I had to ask her what about the voucher - again she buzzed the supervisor. She took the 50c off and walked away. The cashier put the voucher through - AGAIN as 50c. I told her it's wrong and she mumbled something about 50%... WHAT WAS HER TRAINING? She called the supervisor again. Third time now... The supervisor voided the 50c and hallelujah - the voucher went through as R50. BUT - not once in those 3 times did the supervisor greet me - she ignored me completely and they continued to converse in their native language - making me feel very unwelcome. I have worked in the retail section and does not believe in treating customers in such a rude manner.