Lack of service

Shocking after sales service on an Gentec inverter. 3 5 months old at the time of return. I am being told it's batteries even though the inverter smells burnt. N9w wanting to charge me for an assessment on a product that has a 1 year warrantee. No feedback what so ever I have had to call in to get feedback every week. And refusal for a refund. R12500 Is not a small amount of money to have spent.