Worst service you could ever ask for

This is the worst experience I have ever had with any online store! I purchased two Mecer IVR-2400LBKS inverters and when I used them I found that they don't give me the duration of backup power as I expected they would as they don't charge the batteries that I have to full capacity and also shuts the power off way to early. So I decided to return the items for a refund. Only when I contacted them regarding getting the items returned I was told that they can charge up to 50% for the return. This in itself is absolutely ridiculous! The products doesn't perform as I was hoped, it would be a waste to keep them but now it's a waste to send them back as well. So I had no choice to send them back, only to get an answer 2 weeks later that they will be charging be 30% of my order amount for handling fee. That means I'm being charged R1308 juts to return items that's not performing as expected. Now when I asked to give me feedback on when I can at least expect to get my refund even though it's 30% less, now I'm being told that it might take up to 14 days. I've already had to wait for more than 14 days. How is this even legal, where is my consumers rights?? I returned the products within 14 days and now I have to deal with this. I cannot just go out and buy something else in the mean time. This is absolutely ridiculous!!