Terrible product with even worse back up

Purchased a hybrid inverter from Makro 18/09/2022. Inverter keeps tripping with a burning plastic smell when we turned it back on batteries agow full so its not the batteries. 10 days after returning it I have been told extension cord it too heavy for inverter. Well that's laughable coz my television does not run on an extension. And anyone technical would know a extension can be under rated but over rated is probably better. Fact is no extension is used. Pathetic company with even more pathetic technical staff. Would never recommend them.