Double Charged

When I paid for my goods at Clicks I was advised that the transaction was unsuccessful on my credit card although I had received an sms notifying me that the transaction was successful. I however had to pay cash for my goods . The supervisor in charge (Sixpus) told me that I should get a reversal in not less than 3 hours, if not I should come back and they will reverse it since he confirmed that the problem is on their side. I phoned my bank and they confirmed that the transaction was successful and I was given an authorization code. I phoned Sixpus and he advised me that the money did not go through on their side although I had given him the authorization code. My bank statement shows that the transaction was successful. Its been five days trying to get back my money from Clicks with no success. In other words Clicks double charged me and they are failing to show me proof that the transaction was unsuccessful on they side.