Refused to echange damaged good as per agreement

I entered into an agreement for a new phone on contract with a MTN representative (Gabriel) at the Menlyn Mall store in Pretoria.<br> Upon pick up of the phone I was told that if there is a problem with the phone I could return it within 7 days and they would exchange it for a new phone.<br> The phone's auto rotate function does not work. I returned to the store with the phone. Kgothatso inspected the phone and could not get the auto rotate working even though the auto rotate function was clearly switched on. Another representative inspected the phone and had the same result (Lerato).<br> Kgothatso gave the phone to a REP of Huawei whom also could not fix the function. Clearly the phone was faulty.<br> Kgothatso refused to exchange the phone even when it was returned within the 7 days as per Par 2.1 of the MTN Customer Pick-up Document signed by myself and Gabriel upon pick up. I requested that they exchange the phone and was denied a new phone. Kgothatso noted that they had no stock.<br> As a customer I am disappointed in being denied what was agreed upon in a signed contract. I have an email from 2 MTN employees confirming the time and date that they declared the phone faulty.