Bad Warrenty

I bought a 5kw off grid inverter. All was fine until one night it died. The invertor went in as it was stil under warenty and I was informed that there is a two month turn around time. I waited my two months and it was returned with a error it never had before so the shop send it back. Now I was informed that there was a surge. Only problem is all the fuses in the system is fine and is not connected to any eskom power?