Jet Gateway Mall - Extremely Rude & Unprofessional Cashier

We visited Jet at Gateway Shopping Centre on Saturday 03 March. Mpume assisted at cashing stage. We were not done with the transaction & turned around to retrieve additional items. Mpume had already finalized the transaction & requested signature. I informed her that I had a voucher I wanted to make use of, therefore I needed additional items. Mpume queried why we didn't let her know & again requested signature for items. We informed her that we couldnt have 2 separate transactions as we would lose out on the voucher. She called for her manager Shamla & then continued muttering out loud in Zulu. I indicated to her that it was very rude & that she shouldn't take for granted that we don't understand what she's saying (which we did). She eventually cancelled the transaction & proceeded to re-cash(without help from anyone). I again brought to her attention (extremely politely) that she shouldnt do this going forward. My suggestion was completely ignored & no form of apology was shown. She just looked past & called for the next person. I had no intention of informing the manager, but was forced to as Mpume came across extremely rude & unprofessional. She represents the Jet brand & surely if she can't see her error, how on earth will anything be learnt. Staff such as Mpume should be offered more training to deal with such situations. If she felt that customers are wrong - which they sometimes are - she should have dealt with this in a professional manner & not in the way she dealt with it. She is in customer facing role & as such her behavior should be more professional. I was not impressed with her & trust that this was a once off. Please ensure that staff are trained properly & I would suggest that your training includes spot checks. On a side note, staff really should be trained to be more friendlier.