Hi Rowena_Pereira,
I understand that you are seeing an issue with your cellular data usage on your iPhone. Since it seems that you can use this feature, but only on certain apps, I would like for you to first check and make sure all of these apps are authorized to use cellular data in your iPhone settings:
Set whether cellular data is used for apps and services. Go to Settings > Cellular, then turn cellular data on or off for any app that can use cellular data. If a setting is off, iPhone uses only Wi-Fi for that service. The iTunes setting includes both iTunes Match and automatic downloads from the iTunes Store and the App Store.
Cellular settings - iPhone
http://help.apple.com/iphone/9/#/iph3dd5f213
If the issues persist, I would like to recommend following the troubleshooting steps in this article, keeping in mind that you may have to contact your carrier in order to resolve the situation (step #6):
- Check your coverage area to make sure that you're in an area with cellular network coverage.
- If you can't connect to a cellular network on your iPhone, make sure that cellular data is on in Settings > Cellular. On your iPad, go to Settings > Cellular Data.
- If you're traveling internationally, make sure that your device is set up for data roaming. Go to Settings > Cellular > Data Roaming.
- Restart your iPhone or iPad.
- Check for a Carrier Settings Update by going to Settings > Carrier Settings.
- Take out the SIM card and then put it back in. If the SIM card is damaged, or doesn't fit in the SIM tray, contact your carrier.
- If you have another device, see if you can connect your carrier's network with it in that location.
- Contact your carrier to:
- Verify that your account is active and in good standing.
- Make sure there are no outages in your area.
- Check that your device is not blocked from receiving cellular services and set up with the right data plan.
- Update your iPhone or iPad to the latest version of iOS.
If you still can't connect to a cellular network, and have confirmed with your carrier that there isn't an issue with your account or network, try restoring your device.
If you can't connect to a cellular network or cellular data - Apple Support
https://support.apple.com/en-us/HT201415
Thanks for using the Apple Support Communities. Have a good one!
