Excessive General system services data

I am not in my home country and my data plan is 500mb per day.

I reset the cellar statistic every day,

The statistic show system service used all the data. And the category is “General”. 

and the issue keep happened for one week.

I am traveling and use data roaming the excessive background data usage made me cannot use any data outside of hotel after few hours even I did not touch my phone.

I have enable low data mode and disable all auto update/wifi assist/app store using cellular data. What I else i could do? Should i disable all notification? Or disable all app using cellular data?