Terrible service!!!!

This company make no attempt whatsoever to give their customers service. We bought our inverter from them in November 2020. In 2022, the batteries started failing, so we took it to them early December for repair. They took it in saying that it couldn't be fixed before Christmas. They returned it, in February 2023, after charging us a hefty amount, saying that they had replaced the batteries (and although they say anything they had dropped it because the box is damaged!). And it has not worked since they returned it. The charge lasts for approximately 30 minutes (used to be 4 hours) and this from supposedly new batteries (2) They do not answer WhatsApps, or their phones or reply to emails. We don't know what to do!