Refusing to refund Wrong Shoe Size and Giving them away for Charity

I ordered size 7 shoes and i was given size 7 box but Size 8 shoes only realised this error after receiving a new order which was fitting comfortably. I phoned to explain and i was advised to return them which i did. After 3 weeks i was told that they were not going to refund because they were worn but they will give away for charity.