Yesterday I had went to once of Apple store called Epic Center located at Somerset, SG, and the apple's personnel advised adjust on the setting portion and goto cellular --> turn off "Wifi Assist", although since yesterday night I turn it off till now... but on my cellular data portion still active, even I didn't use via it but via Wifi, it consumed about 0.2MB/half hour, like little dipping water from the pipe, if accumulated till a month, to be consumed about 1.5GB (in condition didn't use Cellular but Wifi, but this data still running under Cellular data usage!!), so terrible figure for the user of not use such cellular service for those apps support...
I need a proper solution~~~~ who can help!!~~~~~