Poor customer care

Bought shoes on 3 for 2 sale...2pairs of female crocs * size 6*... the other shoe fits well but the other shoe is big maybe because of the make... Emails Crocs for EXCHANGE. I was told that they do not exchange unless I bring all the shoes I bought. I am amazed because I didn't want refund instead change to a smaller size which I see online that they still have.

I'm so disappointed by this... not sure what to do with this shoe.