No live view

I have two batteried camera which located in hall way and living room, one doorbell. They all work very well untill there is no live view available for hall way and door bell today. Living room works well, i am able to go through to live view. However there are still few notification come up for front doorbell motion but it recored nothing but black screen when i clicked into the video.Tried to see if there is a way to contact something like IT support or techician support unfortunately come back to community support. I am very disappointed with the brand now, what's the purpose to pay $4/device/month and there's no backup? I will sell all these camera ASAP and change to something else more realiable and cheaper to run.