FLLA 3G phone faulty. Telkom will not replace the phone. Have not even had the phone in my possesion for 3 weeks.

I converted from copper to an FLLA 3G Telkom phone end of November 2019. Phone was delivered with 4 days. Only activated 1.5 weeks later. From the first use the recieving person get a very Loud ECHO on their side (no ECHO on my side who made the call. This happens when using the headset or speaker system on the FLLA. It will also at random power down while talking. The phone was taken back to a telkom branch in early December 2019 and sent to Telkom repair centre. Got the phone back late January 2020. Tried it again and the exact same problems occurred. Went in for the 2nd time early February 2020. Received sms to collect phone. Went today and discovered that the repair centre could find no fault. Spoke to the senior lady in charge at the branch and asked them to exchange the phone for a new one. Stated to me they do not have the authority to exchange. I then mentioned the CPA (Consumer Protection Act) as was immediately told that it protects them as well. I stated that the product is faulty and needs to be replaced. They just stated that they will send it in again for the 3rd time. This is totally unacceptable and I should get a new replacement phone. I have tried phoning their customer care, even tried chatting via the computer to them. Unfortunately nobody is able or willing to help.