Return Policy on a broken Phone

I got my new phone last week Monday from my Vodacom insurance claim , I used it this weekend and the phone was constantly freezing , it lagged when I moved from screen to screen I had to reset it to factory setting twice because the phone was just slow , took the phone back to the Vodacom 4U store in Eastgate and was just told they would send it in and I will hear from them , Im not happy as is a new phone and I don’t want a fixed phone I paid my excess fee so I would appreciate a phone that works !! All I was told is they need to send it in to fix it ,which I’m not interested in, if they fix the phone or not , like I said I paid my excess fee I would like to get a new phone that work I took it back with in the 7 day policy , I can’t get hold of Vodacom 4U in Eastgate , I phone the insurance on *** they said they just waiting for a quote from Vodacom , if there is anyone from Vodacom that can get back to me and keep me updated with the status of my phone because i pay my bill every month on time so I don’t appreciate not being without a phone.