cashier did not give back makro and ebucks card

We went to Makro Wonderboom on Saturday before 12:00. We gave the cashier the makro card and the ebucks card. We paid cash and the cashier gave us the slip but no cards. We called to ask if the cards was found when we realised we did not get it back. We were told the cards is not there they will call us if they found it. Makro was our last stop and we did not have the cards after leaving Makro. Why didn't the cashier give the cards back or gave it in at the found counter. What does she want to do with the cards?