New phone - out of box failure

I upgraded my phone to the Sony xperia m4 aqua on the 3rd of September and was delivered the next day. I had to then wait for 2 days for the new sim to be activated to use the phone. Finally on friday the 7th I could eventually use my phone.But i was disappointed to find out that the phone display was damaged - it has vertical screen lines that makes it difficult to see. I reported the problem to cell c call centre and was advised that it will be treated as an out of box failure as it is still within the 7 day return period. The call centre agent told me to take the phone to the nearest cell c store and it will sent away for assessment to be repaired or replaced, I went to Cell c Bayside in tableview and was then told that they cannot take the phone as it is with cell c direct and they are a franchise store. I called the call centre immediately after and was then told i cannot take it to the store but must call Sony customer care direct. I asked the agent why should i be dealing with Sony as the phone is damaged and is within the 7 day period. I was told this was the procedure. I am tire of being given the run around and want cell c to contact me directly and i give me a new phone.