Card Transaction

Today 11/4/2015 I went to checkers to buy some goods. At the till the card machine went offline while my transaction was prosessed. Money went out of my account but did not go through the machine. The teller called on management and they recommended the we do the transaction again although the money already went off my bank account. This being an issue to me as no refund was received. They assured me the refund will come through but could not tell me when and if it didn't I must come back monday with a bank statement. I asked them to phone for authorisation but they refused and said the machines were off nation wide. Yet directly after leaving the shop ( as weel as my shopping) still with no refund my card went through at Food*****s market and crazy store. I now must wait for whenever for MY money to be back in my account without the goods!!!! Worst management ever!!