I WAS CHARGED TWICE AND ONLY MADE 1 PURCHASE

I went to the Edgars Sale Store in West Street, Durban CBD. I purchased 3 items that all came out to R589.85. the cashier was a male, very friendly I must say, although he was crossing the line a bit asking about my salary, which I didn't responded, and then saying things like you must earn a lot of money but then only you know that, and your husband, and weird things like that. he swiped my card the first time and said that it came out denied and that the system was down. we waited a bit and he said it had been like that all day, in and out. So he swiped it again, this time it went through and he returned my card and I signed for him and that was it. We left there and came back to work, later on in the afternoon I checked my phone and saw that I had 2 sms's from my bank showing that I've been charge the same amount twice. at first I thought the sms had been duplicated but then I went in to my account and saw that I had been debited twice. by the time I realized that it was too late to contact anyone. I want my money back and I need this matter to be taken care of ASAP.