Bad customer service

I visited cinecentre recently. The cues were long as usual but it did not bother me as buying popcorn is usually my favorite. When the cashier helped me, she swiped my card but no slip came out as it was out of paper. She replaced it and did not know how to reprint a slip so she swiped again, without really noticing as I was talking to friends. The next morning when I woke up I saw that two transactions went through. When I went back to fix the problem, they did not know what to do nor understood what the problem was. I never got my money back.