When I am using the iphone with cellular data turned off, the telephone function freezes every second day. I need to reset the iphone. Genius bar has told me that this is not an apple issue. The network provider (SoftBank Japan) has told me it is not their problem, but that if I switch on cellular data every day it will go away. Haha!!!!! Anyone elsewhere have the same issue? This is a major issue as I am paying an extra $7 a month for a variable tariff!