Crocs don't fit and don't exchange

I Bought a pair of shoes and when I got home and tried them on found they are not fitting right.I went back to the store where I bought it from [ mall of the north Polokwane] the staff store did not want to help and was rude and kept saying she sold me the shoes but was not her and was a guy and did not want to exchange to bigger size.

This is now that I won't buy cross again and my wife also don't want to buy shoes as don't like how we were treated.