Telkom refuse to replace faulty Samsung A70

My Samsung A70 had a blank screen fault. The phone was about 3 months old. It was sent in for repairs. This took 2 weeks. The phone was formatted and we lost all the data. It worked for a few weeks and then the same fault happened. The same process was followed. It has now happened for a 3rd time with the same process being followed. Telkom refuse to replace the phone and insist that it must be repaired. It is absolutely impossible to speak to Samsung as the line is so bad that you cannot hear anything. We have emailed Shirley at Samsung but have had no response. We couldn't even get a reference from her, barring her name.