Transaction has gone through 4 times

I paid an amount of R820 for the excess on an insurance claim. The credit card machine at the branch wasn't working properly so they needed to put it through again. Bottom line, after much ado, the transaction has now gone though my credit card 4 times. The store stated at the time they would process the refund but, to date this hasn't happened and i am out of pocket to the tune of R2500.