Faulty is their standard

I bought an inverter from First shop in January. the inverter was 3 days old when I realised it wouldn’t charge beyond 40%. I dropped the faulty inverter off at Mustek in midrand and have received no feedback. When I call, I get told that they are inundated with faulty items that need to be repaired so it will take long. I would not recommend anyone buys any from a company that is “inundated with faulty item repairs.”