New iPhone 8 is used 7GB on data last month. No movies or games used. Few calls and texts. Any ideas? So far “experts” have not helped.

New iPhone 8 used 7 GB data last month. Replaced iphone7 that only used .2 per month. No movies or games, just a few calls and texts. Check weather and ball game scores. What is going on????? So far “experts” only say turn off cellular data which really renders phone useless away from home WiFi. Help