Hello,
How can I refresh original firmware or obtain root user and password for ADC-VC826 if I no longer want to use them with ADC and put them to HIKvision as that is who make them for ADC.
Unfortunately no. Many many people have tried to do this and none have succeeded yet. Not necessarily to fully convert to him vision firmware but to use the trap stream in addition to adc cloud. The problem is there is no way to access the cameras interface after it is flashed with adc firmware due to how the firmware is built 
I was able to get to log in screen to the camera on the specific port but need user name and password to log in.
This is kind a sad as if I own the equipment and don’t want to use it on alarm.com I should be able to use it in anything I want it.
How can I refresh original firmware or obtain root user and password for ADC-VC826 if I no longer want to use them with ADC and put them to HIKvision as that is who make them for ADC.
This is not something we can assist with. I don’t remember seeing any success stories trying to do this, ADC cameras are intended for use only with ADC (and are designed that way to secure your video stream)
You might try reaching out to the OEM.