KIC selling defective spares

So KIC are the agents for Whirlpool in South Africa, not sure which is worse, the backup service from KIC or the Whirlpool product its self. I spent over R25k on my whirlpool set of Oven, hob warmer and microwave oven. The oven overheats and trips and the micro. has now burnt out three, what they call, Platine Inverters at R2700 a shot, which brings me to the after service from KIC. The third inverter I replaced did not work from new, the F05 fault still displayed. After having the agents test it, I was told that the inverter is not supplying current to the magnetron. KIC refuses to replace this unit, saying they do not know what happened after it left their sales. Eventually telling me that I am not qualified to fit the part which involves plugging in three sets of wires, which is beside the point, they never pointed this out to me when I requested a quote and even when I collected the part, nowhere on any of their paperwork dos it state this. They eventually just ignore your calls and mails. Absolutely disgusting service to match a terribly unreliable product.