Nations Appliance Repairs review: Scam 1

There is an outfit in Florida that contracts with appliance repair techs in Austin, Texas. You call [protected] and they schedule a visit from a repairman. His name JR Heiss with a phantom company named Longhorn Appliance. Neither of the companies are registered to do business in Texas.
Here the story:

My 5 year old KitchenAid dishwasher blew the control board. I got a quote for 466.00 dlls for parts and labor.
Once repaired, it immediately got fried again. The repairman returned with a new one and a different fuse. Worked for a single washing cycle when it went bad.

So, after paying for parts and services, being quoted for a repair, getting a "one year warranty on the work" the company argues that it is a different problem now, perhaps a short circuit, so I have to pay anew for parts and labor.

To me it seems that the tech missed the diagnosis or did not researched it enough to determine the reason for the control board malfunction. So, we are back to square one but I am out of my money. Needless to say the unprofessionalism of the tech who at one point raised his voice becoming very rude with my wife, who rightfuly asked for a refund.

I called the company to complain but since this is a "new" problem no refund and no repair to be expected.

My question is, how is this a new problem when I still have a fried board and a non functioning dishwasher? Wasn't that the reason for my original service call? What is the rational and logic of these scammers?
It is hard to argue with pinheads.