Rude cashier

I had such a bad experience with a cashier named Joy. she was so rude made me wait for 10 minutes before attending to me she was busy counting her coins. I was there with a petrol voucher i won at work and she told me it declined and when we checked at work voucher was still valid and when i went there again this morning it was like she wanted to jump out of that counter and assault me until a lady came i think it was her manager told her to go and she took over. Am very disappointed at the level of service i received and should i win i again i would rather get something else and not voucher for them. Total garage in Kuilsriver Van Riebeeck road.