It doesn't make sense

For the second time in less than 12 months I have had ********** activity on my Nedbank credit card, ********** using my card to purchase products via the internet. It's bad enough that this happens, but what is so much worst is I cannot stop the payment even though the funds are still in my account. The funds have been allocated for payment so become unusable by me. Even though I have picked up the amount of money that has been **********ly used, Nedbank Card Division tell me that they cannot stop the payment and the funds have to leave my account. Only once the funds have been paid to the merchant can I submit a query and then they investigate, and only after their investigation will they decide if my funds are refundable. Surely there has to be a better way to deal with this? Once payment has been made the merchant will release their goods and the ********* win, once again.... They say crime doesn't pay, I don't think that applies in South Africa - we make it too easy!!