the worst service ever

I bought a cellphone at foschini the glen on the 30th of October within few days I noticed, the volume for incoming calls was very low, I had to put it on loud speaker for calls and it was freezing, I took it back within 7 days and they told me they had to send it to a repair center, now am without a phone and I use this phone for work, how can a brand new phone be sent to repairs and also the inconvenience, I am using this phone daily how am expected to survive without a phone, now am on available on email because they cant be bothered