Storage Problem in iPhone 6 64 GB
Suddenly more than 30 GB Storage has been filled without any apps or documents and showing "Storage Full"
After removing several apps, around 7 GB freed, but within few minutes, again Used Space is showing full automatically. Through iTunes, more than 70% space is showing occupied by Documents & Data, but there is no documents or data. I'm also unable to access Mail, as its automatically closes down just after opening.
Please suggest me what to do?
iPhone 6, iOS 9.2.1