Side step cosmo city

I went there last week Saturday on the 27 November to buy a pair of Nike sneakers for my son and they said no refund but the shoe box they gave us is for the big shoe size the price on the shoes is R1299 but I paid R1499 and when you fit they give you plastic but the shoes are all dirty even the ones I bought and because of the box and the pricing I feel like the shoes are **** I will call the store tomorrow and ask for a full refund. And another thing the code is written on the box with a red pen and my son started doubting if they are original