Terrible service

Hi. I'm a visually handicapped Vodacom Business account holder. I upgraded to a Samsung Galaxy Note 4 end of Dec 2014. Since then, I have experienced sluggish performance, poor sound and microphone quality. To save time, I booked my phone in at the Samsung Smart Care 14th Ave branch on 25/04/15. 5 days later (29/04/15), I received an SMS that my device was ready for collection. Upon collecting, the agent told me that phone's software had been reset to factory default and that was the cause of my problems. After using it the next day, I noted that there was no change with the poor call sound quality. I returned the phone on 02/05/15 and am still without a handset today (12/05/15). I cannot work properly without my phone as it is my business tool! I contacted Vodacom Customer Care and they said that it is within my rights under the CPA to request an exchange within the first 6 months of having the unit via the Vodacom branch I purchased from. I tried this and had no luck. A trip to Vodaworld Customer Care on 09/05/15 was also useless in solving my problem. PLEASE HELP ME! I have called Samsung multiple times to be told that the job is still incomplete. They have never contacted me.