Poor service & support after broken product bought

On 14 September 2019 I bought a wireless keyboard and mouse combo from CNA Menlyn (Pretoria). On 16 September 2019 when I got to my office in Sabie, I unpacked the combo to start using it. I realized that neither the mouse nor the keyboard worked. I checked the mouse and found that the battery cover was broken and that the battery was completely drained. I also found that the battery for the keyboard was completely drained. I immediately communicated this through to CNA via email and on their Facebook messenger.

On Facebook messenger I got the standard response that they will contact me with 48 hours. The following day they responded by asking me my contact details, which I supp****.

Two days later I followed up with them by expressing my disappointment with the lack of service and support from them. No reply except for the automated response that I will get feedback within 48 hours. Nothing happened further. This morning I sent them again a message expressing my total annoyance with their lack of support and service.

Their response: "Hey Martin, we have sent your complaint along with your contact details to the merchant and we are still awaiting feedback. The CNA team has informed us that you sent the complaint in email to CNA info. Once we have received any feedback we will be sure to let you know. Apologies for the inconvenience. We will be sure to follow up with the team today."

What a poor response! Why should I keep following up with them, but nothing happens?! What do they need to follow up with the merchant? It is now a week after I first made contact with them and I still sit with a broken non-working item that I paid for, with no end in sight as to how this will be resolved