Go-tcha Display Not Working

I have had my go-tchas for several months now. One of them is working fine, but the other ones display has quit working. I cannot see the charging symbol or any of the other options on the display screen. The screen is always dark. I cannot figure out what is going on with it. I can still connect it to my pogo app and it still works, but I cannot see anything on it. How do I fix this? Any suggestions?

Also, I cannot get it to connect to the Go-tcha app for updating it.