Poor customer service - no response to emails - SAA

I had a reason to complain after a recent flight from Johannesburg to Mauritius, so I decided to do so on their website. I received an email stating my complaint had been received, a reference number was attached and I was told I would received a formal response. This was in July and to date, despite 4 emails asking for a response, none has been received. Poor customer service from our national carrier. Regards Alex