bad service an communication from Vodacom

We went Into Alberton City Vodacom shop do an upgrade on my boyfriend phone. He upgraded to the Sony Aqua M4 . We were told that if there was a problem with the phone within 7 days from the day you receive it they send it in for a OBF and it takes from 3-5 working days to get feed back. We got the phone on the Tuesaday 09/02/16 on that Saturday the phone stopoed working , i took it in early that Monday morning (within the 7 days of receiving it) they explained it would take 3 to 5 working days to receive an outcome. I keep calling and they keep saying they will contact me later to let me know, they never do.. I get told on the Friday (day 5 of being in) that they will know latest this Tuesday ( 7 working days) my boyfriend has been without any Form of communication for 8 days now as they cut his sim to fit the new phone an did sim swop.. I am so disappointed in Vodacom. We refuse to take the phone back unless it is a brand new one as we did nothing to cause that phone to break it was clearly a factory default.. (on my boyfriends behalf due to no Form of communication)