ignoring my request for a refund on cancelled pmt

Went shopping at PNP a few weeks ago (10/11). The cashier attempted twice to take payment of R263.75. Both times it was cancelled so we paid by bank card. We received the smses stating the amounts had been deducted and have the cancelled slips. Since then I have made countless call to RCS with regards to a refund. They have even charged us interest on this amount. My two most recent calls have been to Aisha and Amanda, still no response after promises of calling back after an in investigation. This is disgusting. We must now pay a monthly installment for an amount they owe us.