Dis-chem Dont Care

I have purchased online from Dis-chem and the invoice totalled R602.22 but an amount of R643.22 was deducted from my card? Subsequently the order was cancelled by dischem without any communication to me. They even said that they credited me and nothing yet reflects in my bank a/c? IT DOES NOT MAKE SENSE to reverse an order and lose a sale of R602 instead of crediting me with R41 of overdeduction?