Duplicate of Transaction

I went on the 24March to Baywest Mall PE I swiped my card for drinks and popcorns transaction went through but another one went off day two days after I was there I went to standardbank to reverse the second payment but I was given ref no.*** it's been two weeks now no answers I'm still waiting and its not the first time this is happening I had similar incident in December I was given a run around between my bank and the shop but it was resolved within 2 days I got my money.