Gentech Industries

I bought a Gentech Inverter from Makro Germiston on 9/12/2022 . I started having trouble with it right from the begining. It took three weeks to fully charge. In April I took it to Gentech and they fixed it in a couple of hours. I got a job card from them telling me the settings were wrong and that the battery was faulty and they replaced it free of charge. The inverter did not long after that. I left it on charge for a couple of days so that it could charge fully. I then started to use it again and it did not last very long. It did not last long after that. It gave one 4 hour and a couple 2 hours and after that tha maximum it lasted was 40 minutes. I switched it off and never used it again. When I took it back to Makro it was for the second time. They made a copy of my proof of purchase receipt. They made a copy and asked me if I wanted to write something And I said I was not interested in having it fixed and that I wanted my money back. I did not want the inverter back because it would probably give me the same trouble as before. They do an assessment and then send you a quote for a new battery because the old battery they say has been affected by sulfation (what ever that means) They say they put a stronger battery on the inverter. Why was this not done when I took it in in the first place. Now they are telling me I mast pay for a new battery. As far as I am concerned this inverter has not worked properly from day one. All I want is to be refunded my money.