Double / Duplicate debits on Credit Card transactions

Dis-Chem Willowbridge have double debited my credit card twice now in three months. Each debit was successful since issued days apart. Luckily ABSA have picked this up and 4 days later recredited me as a duplicate transaction. Why is this happening in the first place. Had ABSA not picked this up I would have a huge admin nightmare in rectifying same. I don't trust Dischem credit card payments anymore. A simple apology will not suffice without an investigation into this disturbing practice.