Brand new Phone Complaint

I have bought a Stylo S551 at your Pepcell store in Parow Centre on 24 December 2017 for R1100. they cashier who helped me said that the battery was flat and that i just have to charge it and was told that was the only phone left of that make.When i got home the phone did not switch on after a charged it. I took the phone back on the 26th December 2017 when a different cashier swapped the batteries and handed me back the exact same phone (the phone had switched on when the batteries were swapped. On Tuesday night 2 January 2018 the died completely and did not want to switch back on after numerous attempts. i took it back the following day explaining the issue. I was told the phone had to be sent for repairs. what i need your company is to tell me how it makes sense for me to Buy a brand new phone and a week into using it , it has to be sent in for repairs???? This is the second time in 2 weeks that i took the phone back How can i buy a brand new phone , use it for a week and have a sent away for repairs because of manufacturing problems and NOT due to negligents ?? I will not settle for this . I want my full refund of R1100. Please note that if 'inspection' is complete and the phone is repaired, I DO NOT WANT IT. I will only come back to the store to get my refund.