Truworths online order nightmare

I placed an order online and the size delivered did not fit I went to Truworths at Maluti Crescent mall in Qwaqwa Free State to send back the order they did but chose store delivery not the initial address I used, I let that slide The order finally came and I received one shoe size 3 and one shoe size 6 I don't understand how a mix up of a size 3 and 6 can be made I sent an email no one rep**** I am very disappointed and upset