Capitec poor service and amounts being charged with no approval

Wife ordered online from Woolworths and paid. Woolworths then had stock issues and Capitec allowed Woolworths to charge another amount to her account without any approval.

When we contacted capitec she was told she must sort it out and get email correspondence for the refund before they refund it. Not sure how woolworths was able to charge additional amounts with no approval but so much for safe online banking.