Refusal to replace brand new faulty phone

My 66 year old mother in law has just upgraded to a Samsung Galaxy S20 and the phone costs R23000. The phone was faulty from day 1. She has been in to the store 7 times to complain during the pandemic, each time risking catching the virus. The phone was sent away for "repairs" and was received back yesterday and the phone is still not working. She has called Vodacom to ask for a new phone and the consultant refuses as it's not procedure. For R23000 it is unacceptable that the phone doesn't work and no one will help her. She has given you the opportunity to fix the phone and it' still faulty. I believe as per the CPA she has the right to demand a new phone. This needs to be sorted out immediately!!