REPAIR NOT COMPLETED OR NO REPOSNE

I have sent my phone in for repair and it was under warranty it is a Vodacom phone and it was brand New and has a software problem which is unacceptable and I was told that I will get it back within 5 days I received a message saying it would be done within 7 to 14 working days and after that period of time I has recieved no information what so ever and I didn't receive any sort of information to know if it was repaired or not and it has been about 4 weeks now and I have a business to run and I'm sitting with a big tablet which is unacceptable and its a waste of my fuel to drive all the way there and back.