New phone damaged

I purchased a blackberry z3 from the Thabazimbi store 1 March 2016. Due to no cellphone signal in the store, I set it up at home via wifi. As soon as the wifi is disconnected the phone showed network error. I returned the phone within 24 hours. It was sent to Rustenburg and there after to Johannesburg. They rep**** and said it was a customers fault. I cannot accept this at all. R2000,00 phone that was a display phone and not sealed for my satisfaction. When I asked for a sealed phone, they said they are not allowed to sell sealed phones! So this phone was damaged when I bought it. The sim card wouldn,'t go in or out without getting stuck. They even tried it themselves. I am very disappointed and will not leave it at that. It's been 20 days... Phone paid and bought, still no phone! Please assist me ASAP.