ridiculous!!!

I have a blackberry under contract. I have already taken the phone in once for the same problem that I am experiencing. they gave me a refurbished phone!!!! the phone was fine for a while and then I started having the same problems again. The phone keeps switching off whilst talking. battery keeps dying. this is insane as I am running a business and I am losing business!!! I have been having the same problem for a few months but did not have the time to take the phone back as it is quite a distance to the closest repair center. coupled with that I lose business when the phone is gone in as I am provided with a loan phone which has whatsapp etc. I am really unhappy with the contract and the pathetic phone on contract. the refurbished phone is even worse. Now while I wait for Vodacom, I lose business.... plus my time running up and down to Alberton which is not close for me.