Warrantee failure.

I bought an Axpert 7.2 Max inverter from DIY Geek. Full Circle Solar is their supplier and they must uphold the warrantee on this supp**** product. It was faulty out of the box with the cooling fan running at an excessive speed at very low load conditions. As I have the same inverter and has installed one at another customer, I am in a perfect position to compare their performance. Three independand people observed and noticed the problem clearly. I returned the inverter to GIY Geek at my own expenses (R264.50). After more than a week I received feedback that "there is nothing wrong" with it. This clearly cannot be correct - three people cannot be wrong!! Previously ordered inverter worked 100% correct with fan speed according to load conditions. I do not know how this is going to play out but I will never do any business with DIY Geek or Full Circle Solar ever again. This is not service at any level especially if items are brand new and under warrantee.