Double billing / poor customer service

I went to buy food at KFC using my debit card i swipped for 49 rands the money went off from my acc and they said i need to swipe again as it is not refecting on their system but i showed them that it has went off they insisted that i swipe again they will reverse it. this was on the 4th of march 2015. Till today i havent recieved any feedback from them or any reversal, she took my details down the food was even bad nore KFC for me. even my friend that i was with told them that will never buy KFC again