I was sold a **** iPhone by Cash crusaders President Square

Went to the website to search for a 2nd hand iPhone, went to the Randburg store and they told me that the phone is in President Square. I called them and I was to told to come to the store on the 27th September. I purchased the phone cash as it seemed to be in good condition. I couldn't connect the phone and was told it needed wifi. At home I struggled to connect it and eventually I took it to Istore in Randburg where I was informed that the phone is ****. I've always used Samsung and there is no way of telling that the phone is **** just by looking at it. I was assured that Cash crusaders is a reputable store and all their items are checked. I was sold a **** iPhone 7 plus for R6500. I'm in shock, I want a full refund and I don't care about your policies, there was nothing about **** phones on your policies and I have lost all trust with your organisation.