BRAND NEW PHONE BROKE IN 7 DAYS

Hi Peter, On 24 October 2015 we bought a cell phone at Vodacom (Tyger Valley branch in Cape Gate centre) and we were told that the phone has a 7 day warranty in which time we can bring it back for a replacement if it was not damaged by ourselves. During this 7 day period the phone broke and we took it back to Vodacom who asked us to go to one of their technicians at the Cape Gate branch. We went and the lady asked us to bring the phone back in the box with all the accessories which we did. She then asked us if we bought the phone from them or the other branch. I said at the other branch and she asked me to take it to them to send away. Unfortunately my daughter's dog got hold of the box and the barcode was not on the box anymore. Because of this the lady said that they will not take the phone back. We now sit with a brand new phone which is totally useless. Can you please help us?