Samsung phones

I bought a phone on the 5-Oct-2017 at Samsung store in Menlyn, I found fault on the phone nd returned it back within 5 days which was the 9-Oct-2017 They refused to give me a new phone whereas the rule says u get a new phone if u brought it back within 7days Up until today on the 1st of November 2017 I still don't have a phone with me which I paid them money cash They are making their fault of phone as if like am the one who damaged it I don't want their phone anymore , I want my money back