Inverters faulty after a week, owner ignoring our request for refund

Absolutely NO after sales service after paying upfront for 2 x inverters in Dec 2022. Both inverters faulty after a week. We were told they come with 1 year warranty! Notified rep and owner on 23rd December that we want a refund after having no feedback from them. Have sent numerous whats app messages since, the messages get read but no response/reply. Have emailed as well. Everyone just washing their hands of us. Don't know what next step should be, report ***** case, or get lawyers involved?