Fridge Freezer cold but not lights, ice or water

I have a Kitchen aid KRMF706ESS01 refrigerator that stopped working. I replaced the evaporator motor fan in the Fridge and that seemed to turn it back on. a few days later the lights turned off inside, fridge was cold, freezer was not and no ice. I called the Kitchen Aid folks and they sent out a repairman - said my fans were good and he disabled the middle compartment (meats and veggies drawer) said sometimes the wiring goes bad and when it does it shuts every thing down. We reset and everything turned back on, lights, water and cooling was great. Then a few mins after he left, the lights turned off, no water, but can hear the fan I replaced still working. I called the repairman and he said try replacing the evaporator motor fan in the freezer. so I ordered that, but mean while another repair man came from a different company to install the freezer motor but said the problem might be the circuit board instead. The board has been on back order for 2 months now.... meanwhile, the fridge is still not functioning and i said I will install the freezer motor myself... but then when i opened the fridge, i noticed everything was cold, still no lights or water or ice, but the freezer was cold as well.... i opened everything up, noticed the coils were cold, has some frost but not frosted over.... i went ahead and replaced the evaporator motor anyway since i was already in there. turned the power back on - lights are on, water is flowing and both fridge and freezer is cold.... i put a cup of water in the freezer and the water froze over..... one hour later, the lights are back off, the water stopped dispensing, but the fridge is still cold, and freezer is still freezing water.... What is going on with this fridge? its top of the line over $3k and only 4 years old. I dont feel like I want to keep replacing a refrigerator every 4-5 years if i get another one like this that matches the rest of my appliance... Please help! thank you