My freezer stops freezing and my refrigerator gets warm

everything defrosted in my freezer and now the refirerator is getting warm, here and there is sounds like something starts up and stops seconds later

Your defrost is not working most likely. We need to unplug and remove the rear panel in the back of freezer and have a look. If frozen over defrost with a hair dryer. Then we need to look at the defrost heater below the ice over evaporator coil. If we need to replace the defrost heater we need to also change the defrost thermostat, Thanks and please rate my solution, Sea Breeze
I'm here if you have more questions.

Sounds like there is something malfunctioning in the defrost sub-system -- there are many possibilities, such as malfunctioning timer or timer circuit board, open heating element, corroded connections, etc.

Charlie