2 shoe sizes in one shoe

I need clarity .... How is it that as a customer I am given w different sizes on 1 shoe( requested for size 6, the box is written size 6)when I was suppose to wear the shoes as I was going to a wedding it's size 5/6.

The staff at rage in Randburg are advising me that they won't refund me my money because it's a sale item. However there is no such on the slip.

I don't any shoes from the store the *********** staff made the error at the end I have to be punished for.

Please can I assistance urgently on the matter.

Regards dissatisfied customer