Rct inverter issue

Unhappy with the service. Purchased a RCT megapower inverter trolley 1kva. It has now been working for an hour or less and takes 15mins to charge. It's still under warranty and upon purchase they said the lifespan is more than 6 months however it's been less than 6 months and it's not working. Returned it 16/09/2023 and was advised to get ready to buy a new battery as they don't replace after 6months. Mine however did not work for up to 6months. Builders Rooderport branch acknowledgement of receipt of goods 138259