USELESS CELLPHONE WARRANTEE

My scholar daughter bought a Samsung phone from CNA Key West in August last year. At the beginning of this year, the phone started giving problems. End Jan I replaced the battery which was swollen to almost double the normal size. Within 3 weeks the same problem started - you can actually see the battery life running down, opened up the phone and the new battery was swollen like the 1st one. We then handed it in at CNA as it is clear to us that the phone is causing the problem, waited 2 weeks only to collect the phone with NO job description at all! It was simply sent back as it was sent in. I then contacted Edcon, they requested me to hand the phone in once again. Guess what - after 2 weeks I got a call from CNA to say the phone is back, and the job card states \tested & working". WILL I HAND IN A PERFECTLY WORKING PHONE???? and sit with a moping teenager for 4 WEEKS? Even the same swollen battery was left in the phone. I have contacted Edcon again but to date have had no reply. Now what I want is simple: either a new phone or a refund - not negotiable. To expect a scholar to pay R1999 with pocket money for a useless piece of ******* is unacceptable."""