Mr Price Online deliver wrong items on orders and then make it an enormous issue to refund shipment costs

I have a problem with Mr Price Online. On 13/04/2016 I have ordered 2 of the same type black pul*****s online (Small & Medium) on my Mr Price account. I received a Black Medium pul***** and a White Small pul*****. On 18/04/2016 I re-ordered the Black Small pul***** and again received a White Small pul*****. I contacted the Online customer care number and talked to Eugene James telling him what happened and requested to have the shipment cost of the second order credited to my account as they every time send me the wrong stuff. He requested that I have to send him prove with photos that I ordered it correctly and they can only give me a gift voucher for the shipment amount that I have to collect in person at the receiving MRP store. As this was not acceptable I talked to Emilin and she said that I have to notify her as soon as I have returned and credited the wrong pul*****s and she will sort out the shipment cost refund. After I credited the wrong pul*****s I phoned in again and left a message for her as she was not available but she never came back to me. So it becomes an enormous issue to get this R5 shipment cost refunded.