Staff threatening customers and terrible service.

The Aston petrol station in Germiston, The Reef road has some of terrible tellers and absolutely getto. How do tellers at the till threaten customers for wanting to served to pay for goods purchased. I am actually writing this as it is the second time I experience this level of behavior at this shop and from ladies, this morning 29 Aug a lady with dreadlocks on her head literally shouted at me and threatened me for trying to ask her to take the coffee slip from the other teller who was busy with another customer whilst I was fetching an energy drink and scan it. I went to the shop to buy coffee and an energy drink but I left aggrieved and threatened. It is not correct that the guys in that service station have to continuously apologize for the ladies rude and disgusting behavior to customers.