Nando's wants you to pay for their incompetence

I placed and order for pick up at Wonder Park on the Nando's using coupons and vouchers with my total being R16 that I had to pay but on arrival I was told to pay R174 which was not the amount on the app. I called customer care and instructed to right an email to resolve the issue. My issue when I ordered the food was due to the fact that I am hungry . I was late for work and the store said I should pay the R174 which I didn't have. The app also had problems a fews days ago for not processing orders on time. Is this fair?