DC one I wanted to exchange but all I got was short changed

I ordered a size 5 through pay just now. From the joburg branch. I then wanted to exchange for a size 6. Judith arranged for collection. And confirmed receipt thereof. But then she asked if she must give voucher or credit. I asked is this how you guys exchange? Then no reply to my email. I reluctantly said credit me. Because I thought they credit then I can purchase. Correct size(just the process of exchange I thought). Only to find out its an actual refund. Then I only recieved R167.00 ftom a R364.00 and Iall I wanted was an exchange. And Judith doesn't even reply to my emails anymore. Why do you ask a customer if they want you to credit ot give a voucher when they want to exchange for another size? What a mess.