Rude employees, unfaithful employees who don't value customers

Today after a long day from Joburg with my husband, we decided to get ourselves McDonald's big Mac just to reward ourselves after along day. We installed the App and to our beautiful surprise we had vouchers, wow amazing right? No. The lady who assisted was very very rude and not helpful at all, she let us redeem our vouchers, she insisted and shouted at my husband to put in the card, when we had asked her prior, OK we did as told after that we asked her she was cold, I still have the vouchers but I will never go there unless Mc Donald fox this, and speak with thier employees and refund us or something bcs the burgers were going to 15 each and we given the voucher freely by Mc Donald. Which we ended up paying R 95. 80c from R30.00 which was NOT the intention but thier employees who is Themebekile Shabangu' and her colleagues,