ridiculous service

I purchased a samsung galaxy core prime 28 Aug ,8 sept phone doesn't come on,I take it back thinking it would be replaced,however was told it has to be sent for repairs,listening to the regional manager Hynns promising 7-14 working days,I hear daily feedback from the store manager telling me same story,my phone needed a new screen and another part wen I called Vodacomrepair center umhlanga, mMalcolm so called manager told me he understands and would replace it ,however the manager from store says she is still awaiting a credit note to replace it,when I call Malcolm again he says that he would email samsung to find out whats the delay,when I call the number they said they only received the request that day so Malcolm **** to me that it would be replaced,they just been telling me nonsense so I would not bother them,still don't have my phone manager calls me again today to tell me they still waiting to hear from samsung to say they can replace it yet they tell me they don't speak to people direct they can only email them requesting stuff,which I think is utter nonsense that's impossible ,please help I even spoke to a lawyer and a lady named Jeanette at consumer act.