No fuel for R 500

My fiance went to Astron on Witkoppen. She indicated to fill in R500. They checked the tires and did the windows. She then paid and drove a few metres forward and noticed her petrol light was still on. She showed the petrol attendant who agreed no fuel was put in. Asked to pull to another one. They filled in R 500 but wanted her to pay again. After arguing they reluctantly agreed they were wrong. Not a pleasant experience.