31 Days waiting for phone replacement

I booked my Samsung S5 mini within the first week of buying my phone cash as an out of the box failure to be replaced. It I now 31 days and in for the 3rd booking. all because they made mistakes internally. First time it was booked they said my phone had a locked code on and obf was inconclusive, I have proof they had my pin etc. second time it was booked in wrong for repairs, also an internal fault. And now it is in for the 3rd time, despite numerous attempts to resolve this matter, I have now been waiting an additional 9 days and there is no end in sight for when I will receive a new phone. They are ignoring me and sending me the same conclusion, your matter has been escalated. i don't know what to do anymore. i am a sales rep and now i am experiencing a loss of revenue due to dealing with a faulty phone. this is my 2nd hello peter posting regarding the same posting. and i bet i will receive another. we apologise for your convenience, your matter has been escalated. I am tired and don't know what to do anymore..... Please help.