Bad customer service

On the 6th of June 2015 i bought items from lovisa in pavillion , it was marked 3 for R100 , i swiped my card and took the items and went home, the items were a gift for a friends party so i gave it to my friend later on that day , the next day whilst doing cellphone banking i noticed i was over charged for the items instead of charging 100 they charged me 300 , i was out raged at the fact that i had to waste money and fuel to go to pavilion again , when i reached the cashier, she said i have to present the items , i explained i do not have it as it was a gift but i showed her the receipt from the till and the card machine that showed she over charged she still insisted i bring the item and i said , she then did not even tell me what shes doing and phoned someone , thereafter she made me sign something and gave my money back as if i was inconveniencing her , then i asked her if we can speak to the manager about her bad attitude and to my surprise she answers she is the manager. I then said i will complain about her attitude she never even apologize for inconveniencing me.