Duplicate payment for one online order

I was purchasing a few only two items from Shein which cost me about R493 for both but then when I check the statement it show Capitec allowed my money to be debited twice, so instead of one R493 leaving my account there's a duplicate payment for the one purchase.. How can they allow duplicate payment for one purchase, making me feel like my money is not safe with them.. I even have evidence of all this..