Hello Bizier2teach,
Thank you for using Apple Support Communities! I understand that your iPhone is using a higher than expected amount of cellular data, and you're also unable to view the cellular data usage under your iPhone settings. I would be happy to help provide steps to take next.
If you're not able to view your cellular data usage following the steps in Check the cellular data usage on your iPhone and iPad, you can also try going to Settings > Cellular. Check if you have an option to tap on "Carrier Services." If your carrier offers it, tap on "View My Data" next. You'll then receive a SMS with your current cellular data usage. This option may also be found under Settings > Phone > [carrier name] > Services.
If you're still not able to track your cellular data usage, or it's higher than expected, I'd like to have you reach out to Apple Support next:
Get Support
Take care.