Money deducted 2 times on failed transaction

Yesterday morning, I purchased a gift for my wife online at Yuppiechef (1 Dec). When I used my discovery card to pay, it failed with the message "Insufficient funds". So I paid with another card. I immediately went to my online bank to see whats going on. Only to see that they money has been deducted, even though it did not go through. No matter how much I tried, no one could do anything about the R499 being deducted. Yesterday afternoon I got an SMS stating reversal of funds. When I looked, discovery did not reverse the deduction, they just deducted the money again! When I phone, no one can help me, the system is down constantly. I phoned again this morning, and they could not tell me if this would be rectified as it depends on a system fix and they don't know when this will happen. So basically Discovery took a R1000 out of my account, and they are in no rush to fix it, since they are getting interest from this! I will not pay a cent on that card trust me. You want to form your own bank but can't even run your systems. Pathetic