It would be best if you are able to get a copy of the troubleshoot file of the device not having network connectivity. Don't reboot it so that we can investigate what is happening with the device. Also, it's odd it's responding ping even though the mobile data connection state is disconnected?
If it's not possible try to execute SMS commands to turn off and turn on the mobile network.
after 3 minutes execute
See if it changes the result.
If not it's best to get a copy of the troubleshoot file