Pick n Pay - Poor customer service

I went to pick'n pay local as usual to purchase tea time snacks and get some cash as well. When i got to the till i asked for some cash however i was told there is no cash. This was not the case since i had seen the cash in the register was more than enough for the R500,00 i needed. this was the first time it ever happened to me at this store. I used it almost everyday and the staff members are always super friendly.