Insulting customers and bad customer service

I'm utterly shocked and disgusted at how one of the cashiers at Pep(cell) mistreated and disrespected the customers today when I queued to buy airtime. She would leave her work station and go converse with two ladies who seemed to be registering simcards for RICA in the shop, this time the queue is as long as river Nile. I've never queued for more than 5mins at this store but today I was on that queue for close to 30mins. When two of the guys who were in front asked her to attend to the customers, she asked them can't they see that she's busy (entertaining her friends) and she's not intimidated by a bunch of dirty customers, she serves better customers than them, she pointed to other customers who didn't call her out on the service she was giving. I have never been so disgusted by customer service (or lack of) and mostly by the insult she threw at those poor guys.