Bad quality products with no after-sales support

I bought a number of home automation devices from systemgo.co.za. Some of the motion sensors never worked properly and three of the wall switches have stopped working, amongst other issue. The owner (Barry) has been promising to send replacements for months, but after many follow-up emails, calls and messages, he now does not respond at all, while we sit with useless devices that cost us thousands of Rands.