Could not call.......solution
Cannot call even I have enough balance on my account and WiFi connection. Yesterday I was able to call Japan but cannot today. Same situation same number to call. Hard to use it. I do not know why. *After this happened I tried re-download apps couple times, having hard time to download so I stoped. But next day, I tried one more time and successfully download it without any problem and it looks ok. I will try call to the same number.