Inconvenience of Note

I just had a bad experience at Foschini in Mall of Africa. The shop closes at 20h00 and we were still inside the shop. We get to the tills and there's 1 cashier, after 15mins of waiting, get to the cashier and she tells us that she cannot accept cash as they had already cashed up. I had to leave one of the items I wanted cos I was told that if they take cash it must not require change. My question is how do they all cash up before ensuring that they had served everyone inside the shop? Is it your policy to tell customers that you can only take cards? So what if I only use cash ? Honestly worst service ever!