double charging

I went to buy food for my kids and I paid so the cashier swiped my card and I heard her say it went through it said approved still she told me to swipe again and then I have to go get a statement from the bank to come and get my money back I am a very busy person and I don't have time to stand in bank quese so now I have to go out of my way to go to a bank. I can't even go to lunch during the day where must I get time to go to a bank. This is not right towards me. It costs me feul money to drive there and precious time off from my work. I don't feel satisfied about this at all. Can you please help me sort this out.